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A wrapper script to drop to the supported shells or execute shell script files or their text passed as an argument with superuser (root) context in termux

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sudo

sudo is a wrapper script to drop to any supported shell or execute shell script files or their text passed as an argument with superuser (root) context in Termux App. Check the Usage and Command Types sections for more info on what type of commands can be run. sudo stands for superuser do.

The device must be rooted and ideally Termux must have been granted root permissions by your root manager app like SuperSU or Magisk for the sudo script to work.

Make sure to read the Worthy Of Note section, specially the RC File Variables section. This is very important, specially if you were previously using termux-sudo by st42.

To use sudo with Termux:Tasker plugin and RUN_COMMAND Intent, check Termux:Tasker Setup Instructions section for details on how to them up. The Tasker App or your plugin host app must be granted com.termux.permission.RUN_COMMAND permission. The sudo script must be installed at $PREFIX/bin/sudo. The allow-external-apps property must also be set to true in ~/.termux/termux.properties file since the $PREFIX/bin/sudo absolute path is outside the ~/.termux/tasker/ directory. For android >= 10, the Termux App should also be granted Draw Over Apps permission so that foreground commands automatically start executing without the user having to manually click the Termux notification in the status bar dropdown notifications list for the commands to start. Check Templates section for template tasks that can be run used to run sudo from Termux:Tasker plugin and RUN_COMMAND Intent.

Note that this sudo by agnostic-apollo, termux-sudo by st42 and tsu by cswl are competing packages/scripts and ideally only one of them should be used. Also note that when you install or update tsu, it creates a symlink at $PREFIX/bin/sudo for its own sudo command. So installing or updating tsu after installing sudo by agnostic-apollo will replace the sudo by agnostic-apollo script file with the tsu symlink and installing sudo by agnostic-apollo if you have already installed tsu will break its own sudo command.

If you want to run commands in termux user context, check tudo.

Contents

Dependencies

Using sudo directly from inside termux terminal session does not have any specific version requirements, other than bash version >= 4.1. However, to use sudo with Termux:Tasker plugin and RUN_COMMAND Intent requires the following versions to be installed. Check Passing Arguments section and Termux:Tasker Setup Instructions section for details.

Downloads

Latest version is v0.1.0.

Install Instructions For Termux In Android

The sudo file should be placed in termux bin directory /data/data/com.termux/files/usr/bin.
It should have termux uid:gid ownership and have executable 700 permission before it can be run directly without bash.

  1. Download the sudo file.

    • Download to termux bin directory directly from github using curl using a non-root termux shell.
      Run pkg install curl to install curl first.

      • Latest release:

        curl -L 'https://github.com/agnostic-apollo/sudo/releases/latest/download/sudo' -o "/data/data/com.termux/files/usr/bin/sudo"

      • Specific release:

        curl -L 'https://github.com/agnostic-apollo/sudo/releases/download/v0.1.0/sudo' -o "/data/data/com.termux/files/usr/bin/sudo"

      • Master Branch may be unstable:

        curl -L 'https://github.com/agnostic-apollo/sudo/raw/master/sudo' -o "/data/data/com.termux/files/usr/bin/sudo"

    • Download sudo file manually from github to the android download directory and then copy it to termux bin directory.

      You can download the sudo file from a github release from the Assets dropdown menu.

      You can also download it from a specific github branch/tag by opening the sudo file from the Code section.
      Right-click or hold the Raw button at the top and select Download/Save link.

      Then copy the file to termux bin directory using cat command below or use a root file browser to manually place it.

      cat "/storage/emulated/0/Download/sudo" > "/data/data/com.termux/files/usr/bin/sudo"

  2. Set termux ownership and executable permissions.

    • If you used a curl or cat to copy the file, then use a non-root termux shell to set ownership and permissions with chown and chmod commands respectively:

      export termux_bin_path="/data/data/com.termux/files/usr/bin"; export owner="$(stat -c "%u" "$termux_bin_path")"; chown "$owner:$owner" "$termux_bin_path/sudo" && chmod 700 "$termux_bin_path/sudo";

    • If you used a root file browser to copy the file, then use su to start a root shell to set ownership and permissions with chown and chmod commands respectively:

      export termux_bin_path="/data/data/com.termux/files/usr/bin"; export owner="$(stat -c "%u" "$termux_bin_path")"; su -c "chown \"$owner:$owner\" \"$termux_bin_path/sudo\" && chmod 700 \"$termux_bin_path/sudo\"";

    • Or manually set them with your root file browser. You can find termux uid and gid by running the command id -u in a non-root termux shell or by checking the properties of the termux bin directory from your root file browser.

Current Features

  • Allows dropping to an interactive shell in termux user context for any of the supported Interactive Shells with priority to either termux or android binary and library paths.
  • Allows running single commands in superuser (root) context without having to start an interactive shell.
  • Allows passing of script file paths or script text as arguments for any of the supported Script Shells to have them executed in termux user context without having to create physical script files first for the later case, like in ~/.termux/tasker/ directory for Termux:Tasker.
  • Automatic setup of home directories, rc files, history files and working directories with proper ownership and permissions.
  • Automatic setup of the shell environment and exporting of all required variables including LD_PRELOAD so that termux commands work properly, specifically if being run from Termux:Tasker or RUN_COMMAND Intent.
  • Provides a lot of Command Options that are specifically designed for usage with Termux:Tasker and the RUN_COMMAND Intent.

Planned Features

-

Usage

sudo is a wrapper script to drop to the supported shells or execute
shell script files or their text passed as an argument with super
user (root) context in termux.


Usage:
  sudo [command_options] su
  sudo [command_options] asu
  sudo [command_options] [-p] <command> [command_args]
  sudo [command_options] -s <core_script> [core_script_args]


Available command_options:
  [ -h | --help ]    display this help screen
  [ --help-extra ]   display more help about how sudo command works
  [ --version ]      display version
  [ -v | -vv ]       set verbose level to 1 or 2
  [ -a ]             force set priority to android paths for path
                     command type
  [ -b ]             go back to last activity after running core_script
  [ -B ]             run core_script in background
  [ -c ]             clear shell after running core_script
  [ -d ]             disable stdin for core_script
  [ -D ]             disable preserve environment for su
  [ -e ]             exit early if core_script fails
  [ -E ]             exec interactive shell or the path command
  [ -f ]             force use temp script file for core_script
  [ -F ]             consider core_script to be a path to script file
                     instead of script text
  [ -H ]             same sudo post shell home as sudo shell home
  [ -i ]             run interactive sudo post shell after running
                     core_script
  [ -l ]             go to launcher activtiy after running core_script
  [ -L ]             export all existing paths in '$LD_LIBRARY_PATH'
                     variable
  [ -n ]             redirect stderr to /dev/null for core_script
  [ -N ]             redirect stdout and stderr to /dev/null for
                     core_script
  [ -o ]             redirect stderr to stdout for core_script
  [ -O ]             redirect stdout to stderr for core_script
  [ -p ]             set 'path' as command type [default]
  [ -P ]             export all existing paths in '$PATH' variable
  [ -r ]             parse commands as per RUN_COMMAND intent rules
  [ -R ]             use root for searching and validating paths
  [ -s ]             set 'script' as command type
  [ -S ]             same sudo post shell as sudo shell
  [ --comma-alternative=<alternative> ]
                     comma alternative character to be used for
                     the `-r` option instead of the default
  [ --dry-run ]
                     do not execute sudo commands
  [ --export-paths=<paths> ]
                     additional paths to export in PATH variable,
                     separated with colons ':'
  [ --export-ld-lib-paths=<paths> ]
                     additional paths to export in LD_LIBRARY_PATH
                     variable, separated with colons ':'
  [ --force-remount-ro ]
                     force remount rootfs and system partitions back
                     to ro after sudo commands
  [ --hold[=<string>] ]
                     hold sudo from exiting until string is entered,
                     defaults to any character if string is not passed
  [ --hold-if-fail ]
                     if '--hold' option is passed, then only hold if
                     exit code of sudo does not equal '0'
  [ --list-interactive-shells ]
                     display list of supported interactive shells
  [ --list-script-shells ]
                     display list of supported script shells
  [ --no-create-rc ]
                     do not create rc files automatically
  [ --no-create-hist ]
                     do not create history files automatically
  [ --no-hist ]
                     do not save history for sudo shell and sudo post
                     shell
  [ --no-log-args ]
                     do not log arguments and core_script content
                     when verbose mode is enabled
  [ --no-remount-ro ]
                     do not remount rootfs and system partitions back
                     to ro after sudo commands
  [ --keep-temp ]
                     do not delete sudo temp directory on exit
  [ --post-shell=<shell> ]
                     name or absolute path for sudo post shell
  [ --post-shell-home=<path> ]
                     absolute path for sudo post shell home
  [ --post-shell-options=<options> ]
                     additional options to pass to sudo post shell
  [ --post-shell-post-commands=<commands> ]
                     bash commands to run after sudo post shell
  [ --post-shell-pre-commands=<commands> ]
                     bash commands to run before sudo post shell
  [ --post-shell-stdin-string=<string> ]
                     string to pass as stdin to sudo post shell
  [ --remove-prev-temp ]
                     remove temp files and directories created on
                     previous runs of sudo command
  [ --script-decode ]
                     consider the core_script as base64
                     encoded that should be decoded before execution
  [ --script-name=<name> ]
                     filename to use for the core_script temp file
                     created in '.sudo.temp.XXXXXX' directory instead
                     of 'sudo_core_script'
  [ --script-redirect=<mode/string> ]
                     core_script redirect mode for stdout and stderr
  [ --shell=<shell> ]
                     name or absolute path for sudo shell
  [ --shell-home=<path> ]
                     absolute path for sudo shell home
  [ --shell-options=<options> ]
                     additional options to pass to sudo shell
  [ --shell-post-commands=<commands> ]
                     bash commands to run after sudo shell for script
                     command type
  [ --shell-pre-commands=<commands> ]
                     bash commands to run before sudo shell
  [ --shell-stdin-string=<string> ]
                     string to pass as stdin to sudo shell for script
                     command type
  [ --sleep=<seconds> ]
                     sleep for x seconds before exiting sudo
  [ --sleep-if-fail ]
                     if '--sleep' option is passed, then only sleep if
                     exit code of sudo does not equal '0'
  [ --su-env-options=<options> ]
                     additional options to pass to su that sets up the
                     sudo environment
  [ --su-run-options=<options> ]
                     additional options to pass to su that runs the
                     final sudo command_type command
  [ --title=<title> ]
                     title for sudo shell terminal
  [ --work-dir=<path> ]
                     absolute path for working directory


Set verbose level to 1 or 2 to get more info when running sudo command.

Pass '--dry-run' option with verbose mode enabled to see the commands
that will be run without actually executing them.

Visit https://github.com/agnostic-apollo/sudo for more help on how
sudo command works.



The 'su' command type drops to an interactive shell in superuser (root)
context for any of the supported interactive shells. To drop to a root
'bash' shell, just run 'sudo su'. The priority will be set to termux
bin and library paths in '$PATH' and '$LD_LIBRARY_PATH' variables.
Use the '--shell' option to set the interactive shell to use.


The 'asu' command type is the same as 'su' command type but
instead the priority will be set to android bin and library paths in
'$PATH' and '$LD_LIBRARY_PATH' variables.
Use the '--shell' option to set the interactive shell to use.


The 'path' command type runs a single command in superuser (root)
context. You can use it just by running 'sudo <command> [command_args]'
where 'command' is the executable you want to run and 'command_args'
are any optional arguments to it. The 'command' will be run within a
'bash' shell. Priority is given to termux bin and library paths unless
'command' exists in '/system' partition.
To call the 'su' binary, run the 'sudo -p su [user]' command.


The 'script' command type takes any script text or path to a script
file for any of the supported script shells referred as 'sudo shell',
and executes the script with any optional arguments with the desired
script shell. This can be done by running the
'sudo -s <core_script> [core_script_args]' command.
The 'core_script' will be considered a 'bash' script by default.
The 'core_script' will be passed to the desired shell using
process substitution or after storing the 'core_script' in a temp file
in a temp directory in 'sudo shell' home
'$HOME/.sudo.temp.XXXXXX/sudo_core_script' and passing the path to
the desired shell, where 'XXXXXX' is a randomly generated string.
The method is automatically chosen based on the script shell
capabilities. The '-f' option can be used to force the usage of a
script file. The '-F' option can passed so that the 'core_script'
is considered as a path to script file that should be passed to
'sudo shell' directly instead of considering it as a script text.
Use the '--shell' option to set the script shell to use.
Use the '--post-shell' option to set the interactive shell to use if
'-i' option is passed.


Run "exit" command of your shell to exit interactive shells and return
to the termux shell.

Command Types

su

The su command type drops to an interactive shell in superuser (root) context for any of the supported Interactive Shells. su stands for substitute user which in this case will be the superuser (root). To drop to a root bash shell, just run sudo su. The priority will be set to termux bin and library paths in $PATH and $LD_LIBRARY_PATH variables. Check the PATH and LD_LIBRARY_PATH Priorities section for more info.

Note that su is just a command type and does not represent the su binary itself. Use the path command type to run the sudo -p su [user] command instead for calling the su binary.   

asu

The asu command type is the same as su command type but instead the priority will be set to android bin and library paths in $PATH and $LD_LIBRARY_PATH variables. Check the PATH and LD_LIBRARY_PATH Priorities section for more info.   

path

The path command type runs a single command in superuser (root) context. You can use it just by running sudo <command> [command_args] where command is the executable you want to run and command_args are any optional arguments you want to pass to it.

The command will be run within a bash shell. Priority is given to termux bin and library paths unless command exists in /system partition. sudo <command> will not work if executable to be run does not have proper ownership or executable permissions set that disallows termux user to read or execute it if sudo command itself is being run from the termux context and -R option is not passed. The command must be an absolute path to an executable, or basename to an executable in the current directory or in a directory listed in the final $PATH variable that is to be exported by the sudo command. If it is not found, sudo will exit with an error.

The path command type is of course useful for running single commands with root context without having to drop to a root shell, but its also very useful for running commands in /system partition that require priorities to be set to android library paths and which fail otherwise with errors like CANNOT LINK EXECUTABLE and cannot locate symbol some_symbol referenced by /lib..... The sudo command will automatically detect if the command exists in /system partition and set priorities to android bin and library paths in $PATH and $LD_LIBRARY_PATH variables. So running sudo dumpsys will just work. You can also force setting priority to android paths by passing the -a option or to run a binary in /system partition instead of that in termux bin paths.

You can also use sudo <command> even if you are inside of a sudo su root shell and it will work without having to switch to sudo asu or exporting variables to change priority.

You can also run the sudo -p su [user] or sudo -p /path/to/su [user] commands to call the su binary for dropping to a shell for a specific user or even run a command for a specific user, like sudo -p su -c "logcat" system. Note that if you do not provide an absolute path to the su binary and just run sudo -p su, then the termux su wrapper script will be called which is stored at $PREFIX/bin/su which automatically tries to find the su binary and unsets LD_LIBRARY_PATH and LD_PRELOAD variables. You can check its contents with cat "$PREFIX/bin/su". The variables will be also be unset by the sudo script if it detects you are trying to run a su binary.

Check the -a and -r command options that can be specifically used with the path command type.   

script

The script command type takes any script text or path to a script file for any of the supported Script Shells referred as sudo shell, and executes the script with any optional arguments with the desired script shell. This can be done by running the sudo -s <core_script> [core_script_args] command. The core_script will be considered a bash script by default.

The script command type is incredibly useful for usage with termux plugins like Termux:Tasker or RUN_COMMAND Intent. Currently, any script files that need to be run need to be created in ~/.termux/tasker/ directory, at least for Termux:Tasker. It may get inconvenient to create physical script files for each type of command you want to run. These script files are also neither part of backups of plugin host apps like Tasker and require separate backup methods and nor are part of project configs shared with other people or even between your own devices, and so the scripts need to be added manually to the ~/.termux/tasker/ directory on each device. To solve such issues and to dynamically define scripts of different interpreted languages inside your plugin host app like Tasker in local variables (all lowercase %core_script) of a task and to pass them to Termux as arguments instead of creating script files, the script command type can be used. The termux environment will also be properly loaded like setting LD_PRELOAD etc before running the commands.

The core_script will be passed to the desired shell using Process Substitution or after storing the core_script in a temp file in a temp directory in sudo shell home $HOME/.sudo.temp.XXXXXX/sudo_core_script and passing the path to the desired shell, where XXXXXX is a randomly generated string. The method is automatically chosen based on the script shell capabilities. The -f option can be used to force the usage of a script file. If the temp directory is created, it will be empty other than the sudo_core_script file and will be unique for each execution of the script, which the script can use for other temporary stuff without having to worry about cleanup since the temp directory will be automatically removed when sudo command exits unless --keep-temp is passed. The temp directory path will also be exported in the $SUDO_SCRIPT_DIR environment variable which can be used by the core_script, post shell and --*shell-*-commands options, like --shell-pre-commands='cd "$SUDO_SCRIPT_DIR"'. The $HOME refers to the sudo shell home.

For bash zsh fish ksh python python2 ruby perl lua5.2 lua5.3 lua5.4, process substitution is used by default and for dash sh node php a file is used. If the usage of process substitution is breaking for some complex scripts of some specific shell, please report the issue.

The -F option can be passed so that the core_script is considered as a path to a script file that should be passed to sudo shell directly instead of considering it as a script text.

The core_script can optionally not be passed or passed as an empty string so that other "features" of the script command type can still be used without calling the script shell.

It may also be important to automatically open an interactive shell after the core_script completes. This can be done by using the -i option along with --post-shell* options. The sudo post shell can be any of the supported Interactive Shells and defaults to bash. The same shell as the script sudo shell can also be used for sudo post shell by passing the -S option as long as the sudo shell exists in the list of supported interactive shells. The environment variable $SUDO_SCRIPT_EXIT_CODE will be exported containing the exit code of the core_script before the interactive shell is started. Running an interactive shell will also keep the terminal session open after commands complete which is normally closed automatically when commands are run with the plugin or intents, although the --hold option can also be used for this.

You can define your own exit traps inside the core_script, but DO NOT define them outside it with the --*shell-*-commands options since sudo defines its own trap function sudo_script_trap for cleanup, killing child processes and to exit with the trap signal exit code. If you want to handle traps outside the core_script, then define a function named sudo_script_custom_trap which will automatically be called by sudo_script_trap. The function will be sent TERM, INT, HUP, QUIT as $1 for the respective trap signals. For the EXIT signal the $1 will not be passed. Do not exit inside the sudo_script_custom_trap function. If the sudo_script_custom_trap function exits with exit code 0, then the sudo_script_trap will continue to exit with the original trap signal exit code. If it exits with exit code 125 ECANCELED, then sudo_script_trap will consider that as a cancellation and will just return without running any other trap commands. If any other exit code is returned, then the sudo_script_trap will use that as exit code instead of the original trap signal exit code.

Check the -b, -B, -c, -d, -e, -E, -f, -F, -l, -n, N, -o, O, -r, --remove-prev-temp, --keep-temp, --shell*, --post-shell*, --script-decode, --script-redirect, --script-name command options that can be specifically used with the script command type.

Supported Shells

The bash shell is the default interactive and script shell and must exist at $PREFIX/bin/bash with ownership and permissions allowing termux user to read and execute it. The --shell and --post-shell options can be used to change the default shells. The path command type always uses the bash shell and command options are ignored. Normally, shells are not validated as the root user unless -R is passed so they must have proper ownership or executable permissions set that allows termux user to read and execute them.

The exported environmental variables $SUDO_SHELL_PS1 and $SUDO_POST_SHELL_PS1 can be used to change the default $PS1 values of the shell, provided that the shell uses it. Check the Modifying Default Values section for more info on sudo environmental variables and modifying default values.

Interactive Shells

The supported interactive shells are: bash zsh dash sh fish python ruby pry node perl lua5.2 lua5.3 lua5.4 php python2 ksh

These shells can be used for the su and asu command types like sudo --shell=<shell> su and sudo --shell=<shell> asu and also as post shell for script command type when the -i option is passed like sudo -si --post-shell=<shell> <core_script> to start an interactive shell after script commands complete.

The bash shell is automatically chosen as the default interactive shell if the --shell or --post-shell options are not passed to set a specific shell. You can pass the name of a shell listed in the supported shells list like --shell=zsh or an absolute path like --shell=/path/to/zsh. The $PREFIX/ and ~/ prefixes are also supported, like $PREFIX/bin/zsh or ~/zsh.

For perl, the interactive shell is started using rlwrap, which must be installed. Use pkg install rlwrap to install.

Script Shells

The supported script shells are: bash zsh dash sh fish python ruby node perl lua5.2 lua5.3 lua5.4 php python2 ksh

These shells can be used for the script command type like sudo -s --shell=<shell> <core_script>.

The bash shell is automatically chosen as the default script shell if the --shell option is not passed to set a specific shell. You can pass the name of a shell listed in the supported shells list like --shell=zsh or an absolute path like --shell=/path/to/zsh. The $PREFIX/ and ~/ prefixes are also supported, like $PREFIX/bin/zsh or ~/zsh.

Command Options

The $PREFIX/ and ~/ prefixes are supported for all command options that take in absolute paths as arguments. The $PREFIX/ is a shortcut for the termux prefix directory /data/data/com.termux/files/usr/. The ~/ is a shortcut for the termux home directory /data/data/com.termux/files/home/. Note that if the paths with shortcuts are not surrounded with single quotes, they will expanded by the local shell before being passed to the sudo script instead of the sudo script manually expanding them. Note that ~/ will expand to the shell or post shell home and not the necessarily the termux home if used inside scripts or the *-commands options.

It's the users responsibility to properly quote all arguments passed to command options and also for any values like paths passed inside the arguments, specifically the *-commands and *-options options, so that whitespace splitting does not occur.

Check Arguments and Result Data Limits for details on the max size of arguments that you can pass to sudo script, specifically the size of core_script and its arguments for the script command type.

  • -v | -vv options can be used to increase the verbose level of the sudo command. Useful to see script progress and what commands will actually be run. You can also use verbose mode with the --dry-run option to see what commands will be run without actually executing them.

  • -a option can be used with the path command type to force setting priority to android bin and library paths in $PATH and $LD_LIBRARY_PATH variables. This can be useful for cases when the command is an absolute path but does not exist in the /system partition but still needs priority to be set to android paths or if the command is a just the basename and you want to run the binary in /system partition instead of the one in termux bin path since that will be found first during the search since the $PATH variable will be set to priority to android paths.

  • -b option can be used with the script command type mainly for when commands are to be run in a foreground terminal session from plugins. This will simulate double back button press once the core_script is complete to go to the last activity, first to close keyboard and second to close terminal session. Use this only for short scripts, otherwise the user may have switched from the terminal session to a different app and back buttons simulation would be done inside that app instead.

  • -B option can be used with the script command type to run the core_script in background with & (not the entire sudo command). This can be used with the -i option or even with the --shell-post-commands option. The pid of the background process will be available in the $SUDO_SCRIPT_PID variable. Note that all child processes are killed when sudo exits.

  • -c option can be used with the script command type mainly for when commands are to be run in a foreground terminal session from plugins and an interactive shell session needs to be opened after the core_script is complete with the -i option. This will clear the terminal session once the core_script is complete.

  • -d option can be used with the script command type to disable stdin for the core_script. This will redirect the stdin to /dev/null and unset the $PS1 variable so that the core_script can detect that the stdin is not available and run the script in a non-interactive mode. If the core_script doesn't check if stdin is available or not and still attempts to read, it will receive nothing as input or may even cause exceptions in some script shells if I/O exceptions are not handled properly. Note that when plugin commands are run in a foreground terminal session, then even though keyboard is not shown, stdin is available and can be requested by the script which will then open the keyboard.

  • -D option can be used to disable preserve environment when running su, otherwise environment is always preserved.

  • -e option can be used with the script command type to exit early if core_script fails due to an exit code other than 0 without running any commands meant to be run after the core_script like defined by -b, -c, -i, -l, --post-shell-pre-commands and --post-shell-options command options. If -B is passed, then this is ignored.

  • -E option can be used to exec the su that runs the final sudo command_type command. The commands for --hold and --sleep options and remount to ro commands and any other commands that need to be run after the sudo command_type command will not be run.

  • -f option can be used with the script command to force usage of $HOME/.sudo.temp.XXXXXX/sudo_core_script temp file for storing core_script for debugging or if for reason the shell variant doesn't support process substitution and the sudo command is automatically trying to use it and is failing. It can also be used to provide a unique temp directory that can be used by the core_script which will automatically be deleted after execution.

  • -F option can be used with the script command to consider core_script as a path to script file that should be passed to sudo shell directly instead of considering it as a script text.

  • -H option can be used with the script command type with the -i option to use the same interactive sudo post shell home as the script sudo shell home. This is useful for situations like if you are passing a custom path for sudo shell home and want to use the same for sudo post shell home instead of the default home used by the sudo script. So instead of running sudo -si --shell-home=/path/to/home --post-shell-home=/path/to/home <core_script>, you can simple run sudo -siH --shell-home=/path/to/home <core_script>.

  • -i option can be used with the script command to open an interactive shell after the core_script completes, optionally specified by --post-shell option. If the --post-shell option is not passed, then the shell defaults to bash.

  • -l option can be used with the script command type mainly for when commands are to be run in a foreground terminal session from plugins. This will simulate home button press once the core_script is complete to go to the launcher activity.

  • -L option will export all the additional paths that already exist in the $LD_LIBRARY_PATH variable at the moment sudo command is run while running shells, The default paths exported by sudo command will still be exported and prefixed before the additional paths. You can also use the --shell-pre-commands and --post-shell-pre-commands options to manually export the $LD_LIBRARY_PATH variable with a different priority as long as it doesn't break execution of the shells.

  • -n option can be used with the script command type to redirect stderr to /dev/null only for the core_script (not the entire sudo command). This is a shortcut for --script-redirect=3.

  • -N option can be used with the script command type to redirect both stdout and stderr to /dev/null only for the core_script (not the entire sudo command). This is a shortcut for --script-redirect=4.

  • -o option can be used with the script command type to redirect stderr to stdout only for the core_script (not the entire sudo command). This is a shortcut for --script-redirect=0.

  • -O option can be used with the script command type to redirect stdout to stderr only for the core_script (not the entire sudo command). This is a shortcut for --script-redirect=1.

  • -p option sets path as the command type for sudo and is the default command type.

  • -P option will export all the additional paths that already exist in the $PATH variable at the moment sudo command is run while running shells, The default paths exported by sudo command will still be exported and prefixed before the additional paths. You can also use the --shell-pre-commands and --post-shell-pre-commands options to manually export the $PATH variable with a different priority as long as it doesn't break execution of the shells.

  • -r option will parse arguments as per RUN_COMMAND intent rules. This will by default replace any comma alternate characters ‚ (#U+201A, &sbquo;, &#8218;, single low-9 quotation mark) with simple commas , (U+002C, &comma;, &#44;, comma) found in any command_args for the path command type and in core_script and any core_script_args for the script command type. They will also be replaced in the --hold, --post-shell-home, --post-shell-pre-commands, --post-shell-options, --shell-home, --shell-pre-commands, --shell-post-commands, --shell-options, --script-name, --su-env-options, --su-run-options, --title and --work-dir command options passed after the -r option, so ideally -r option should be passed before any of them. You can use a different character that should be replaced using the --comma-alternative option. Check Passing Arguments Using RUN_COMMAND Intent section for why this is may be required.

  • -R option can be use to enable usage of root for searching and validating paths. This can be useful for cases where the termux user does not have the read or execute permissions to shell or other paths. Starting new su shells for validating paths increases execution time and hence is not done by default.

  • -s option sets script as the command type for sudo.

  • -S option can be used with the script command type with the -i option to use the same interactive sudo post shell as the script sudo shell as long as the sudo shell exists in the list of supported interactive shells. This is useful for situations like if you are running a python script and want to start a python interactive shell after the script completes instead of the likely default bash shell. So instead of running sudo -si --shell=python --post-shell=python <core_script>, you can simple run sudo -siS --shell=python <core_script>.

  • --comma-alternative option can be used to set the comma alternative character to be used for the -r option instead of the default.

  • --dry-run option will enable dry running of the sudo script. This will not execute any commands, nor will rc files, history files or working directory passed be created. However, the sudo shell home and $HOME/.sudo.temp.XXXXXX/sudo_core_script file will still be created if sudo_core_script file needs to be created. It's advisable to also pass the -v or -vv options along with this to see script progress and what commands would actually have been run. Passing --keep-temp may also be useful.

  • --export-paths option can be used to set the additional paths to export in $PATH variable, separated with colons :. The string passed must not start or end with or contain two consecutive colons :.

  • --export-ld-lib-paths option can be used to set the additional paths to export in $LD_LIBRARY_PATH variable, separated with colons :. The string passed must not start or end with or contain two consecutive colons :.

  • --force-remount-ro will enable force remount of rootfs / and system /system partitions back to ro mode in Global namespace after sudo commands complete regardless of if they were mounted as rw or ro when sudo command was run and were mounted as rw due to home or working directories in those partitions.

  • --hold[=<string>] option can be used to make sudo script hold the terminal and not exit until the string is entered. The string can only contain alphanumeric and punctuation characters without newlines specified by [:alnum:] and [:punct:] bash regex character classes. If only --hold is passed, then sudo will exit after any key is pressed. This is useful for cases where sudo is being run in a foreground terminal session, like from plugins and the terminal closes as soon as the sudo exits, regardless of if sudo failed or was successful without the user getting a chance to see the output.

  • --hold-if-fail option can be used with the --hold option to only hold if exit code of sudo does not equal 0.

  • --list-interactive-shells option can be used to display the list of supported Interactive Shells and exit.

  • --list-script-shells option can be used to display the list of supported Script Shells and exit.

  • --no-create-rc option will disable automatic creation of rc files for sudo shell and sudo post shell if they are missing.

  • --no-create-hist option will disable automatic creation of history files for sudo shell and sudo post shell if they are missing.

  • --no-hist option will try to disable history loading and saving for sudo shell and sudo post shell depending on shell capabilities. Not all interactive shells have history support or of disabling it. The history files will also not be created automatically if they are missing.

  • --no-log-args option can be used with the path or script command type to disable logging of arguments and core_script content when verbose mode is enabled. This is useful in cases where the arguments or core_script content is too large and it "hides" the other useful log entries due to terminal session output buffer limitations.

  • --no-remount-ro will disable remount of rootfs / and system /system partitions back to ro mode in Global namespace after sudo commands complete if they were mounted as rw when sudo command was run due to home or working directories in those partitions.

  • --keep-temp option will disable automatic deletion of the sudo temp directory $HOME/.sudo.temp.XXXXXX on exit. This can be used to debug any temp script files created.

  • --post-shell=<shell> option can be used with the script command type to pass the name or absolute path for sudo post shell to be used with the script command type and the -i option.

  • --post-shell-home=<path> option can be used with the script command type to pass an absolute path for the sudo post shell home that overrides the default value.

  • --post-shell-options=<options> option can be used with the script command type to set additional options to pass to sudo post shell while starting an interactive shell.

  • --post-shell-post-commands=<commands> option can be used with the script command type to set bash commands to be run after the sudo post shell exits.

  • --post-shell-pre-commands=<commands> option can be used with the script command type to set bash commands to be run before the sudo post shell is started. The commands are run after the commands that are run for the --shell-post-commands, -b, -l and -c options.

  • --post-shell-stdin-string=<string> ] option can be used with the script command type to set the string that should be passed as stdin to the sudo post shell using process substitution or herestring depending on shell capabilities. Some shells when run in interactive mode may automatically exit after running the commands received through stdin or may not even accept strings from stdin. This option is used for automated testing.

  • --remove-prev-temp option can be used with the script command type to remove temp files and directories created on previous runs of sudo command that may have been left behind due to sudo being killed and not cleanly exiting, or Termux crashing or being killed by android OOM killer or the phone rebooting as long as the sudo shell home is not changed.

  • --script-decode option can be used with the script command type so that the core_script passed is considered as a base64 encoded string that should be decoded and stored in temp file. The temp file path is passed to the script shell. This can be useful to pass a script whose normal decoded form contains non UTF-8 or binary data which if passed directly as an argument may be discarded by the shell if not encoded first since such data cannot be stored in bash variables. If this is passed, then -r option processing will be ignored for the core_script but not for any arguments.

  • --script-name option can be used with the script command type to set the filename to use for the core_script temp file created in $HOME/.sudo.temp.XXXXXX/sudo_core_script directory instead of sudo_core_script. The temp file path is passed to the script shell if -f or --script-decode is passed or if the script shell doesn't support process substitution or if core_script passed contained non UTF-8 or binary data.

  • --script-redirect=<mode/string> option can be used with the script command type to set the redirect mode or string for stdout and stderr for the core_script. The following modes are supported:

    • 0 redirect stderr to stdout. This can be used to receive both stdout and stderr in a synchronized way as stdout, like in %stdout variable for Termux:Tasker plugin for easier processing of result of commands.

    • 1 redirect stdout to stderr. This can be used to receive both stdout and stderr in a synchronized way as stderr, like in %stderr variable for Termux:Tasker plugin for easier processing of result of commands.

    • 2 redirect stdout to /dev/null. This can be used to ignore stdout output of the core_script.

    • 3 redirect stderr to /dev/null. This can be used to ignore stderr output of the core_script.

    • 4 redirect stdout and stderr to /dev/null. This can be used to ignore stdout and stderr output of the core_script.

    • 5 redirect stderr to stdout and stdout to stderr. This can be used to swap stdout and stderr output of the core_script.

    • 6 redirect stderr to stdout and stdout to /dev/null. This can be used to ignore stdout and to receive stderr output as stdout of the core_script.

    • * else it is considered a string that's appended after the core_script and its arguments. This can be used for custom redirection, like redirection to a file and possibly used along with the --shell-pre-commands option if some prep is required.

    Note that anything sent to stdout and stderr outside the core_script shell will still be sent to stdout and stderr and will be received in the %stdout and %stderr variables for Termux:Tasker plugin, so do not ignore them completely while checking for failures.

    If you are using SuperSU and running commands in an interactive shell like from a foreground terminal session, then these options will not work properly. Check Automatic redirection of stderr to stdout in SuperSU for more details.

  • --shell=<shell> option can be used to pass the name or absolute path for sudo shell. For su and asu command types, this is refers to the interactive shell. For script command type, this refers to script shell that should run the core_script. For path command type, this option is ignored.

  • --shell-home=<path> option can be used to pass an absolute path for the sudo shell home that overrides the default value.

  • --shell-options=<options> option can be used to set additional options to pass to sudo shell. For su and asu command types, these will be passed while starting an interactive shell. For script command type, these will be passed while starting the script shell that will be used to passed the core_script. For path command type, these options are ignored.

  • --shell-post-commands=<commands> option can be used with the script command type to set bash commands to be run after the sudo shell running the core_script exits. The commands are run before the commands that are run for the -b, -l, -c and --post-shell-pre-commands options.

  • --shell-pre-commands=<commands> option can be used to set bash commands to be run before the sudo shell is started. For su, asu and path command types, these commands must be simple commands, (preferably one liners) where each command must end with a semicolon ; since they are passed using the -c option to su that is running a bash shell using its --shell option. For the script command type, these can be more complicated, like a bash script itself, since they are passed to a new bash shell in a pseudo file. The commands are run after the cd command for --work-dir is run.

  • --shell-stdin-string=<string> ] option can be used with the su asu and script command type to set the string that should be passed as stdin to the sudo shell using process substitution or herestring depending on shell capabilities. Some shells when run in interactive mode may automatically exit after running the commands received through stdin or may not even accept strings from stdin. This option is used for automated testing.

  • --sleep=<seconds> option can be used to make sudo script to sleep for x seconds before exiting. Seconds can be an integer or floating point number that is passed to the sleep command. This is useful for cases where sudo is being run in a foreground terminal session, like from plugins and the terminal closes as soon as the sudo exits, regardless of if sudo failed or was successful without the user getting a chance to see the output.

  • --sleep-if-fail option can be used with the --sleep option to only sleep if exit code of sudo does not equal 0.

  • --su-env-options=<options> option can be used to set additional options to pass to su that set up the sudo environment. The -c option and user argument is not supported. Use sudo -p su [user] command instead.

  • --su-run-options=<options> option can be used to set additional options to pass to su that runs the final sudo command_type command. The -c option and user argument is not supported. Use sudo -p su [user] command instead.

  • --title=<title> option can be used to set the title for the foreground terminal session, that is shown in the termux sidebar.

  • --work-dir=<path> option can be used to set the absolute path for working directory for the sudo shell. The cd command is run before the commands passed with --shell-pre-commands and --post-shell-pre-commands options are run. The directory will be automatically created if missing.

Shell Home

The default $HOME directory for sudo shell and sudo post shell is /data/data/com.termux/files/home/.suroot. The --shell-home and --post-shell-home options or the exported environmental variables $SUDO_SHELL_HOME and $SUDO_POST_SHELL_HOME can be used to change the default directory. The home directory should ideally be different from the termux home directory to keep config, rc and history files separate for the root user and the termux user. The home directory should also be owned by the root user and have 0700 permission so that non-root users cannot access it for security reasons and hence termux home should ideally not be used.

Check the Modifying Default Values section for more info on sudo environmental variables and modifying default values.

If the home directory is under the termux files directory, then it must not be one of the following directories: ~/.{cache,config,local,termux} and $PREFIX/*.

The home directory is automatically created when sudo command is run if it does not exist. The root:root ownership and 700 permission is also set to it.

If the home or working directories are in android rootfs / partition or android system /system partition, then the respective partition is automatically remounted as rw in the Global namespace when sudo command is run and remounted back to ro before sudo command exits, but only if the partition was mounted as ro before sudo command was run or --no-remount-ro was not passed. The --force-remount-ro option can be passed to force remounting to ro regardless of partition mount state before sudo command was run. For android >= 10, do not set home or working directory in rootfs or system partition since sudo script will exit with error. In android >= 10, rootfs partition is likely a read-only system-as-root SAR partition and system partition is likely an ext4 dedup filesystem which cannot be remounted as rw.

If the -E option is passed or an exec is manually done, then remounting back to ro will not happen.

Shell RC Files

The following shell rc files are used for different shells depending on if sudo shell or sudo post shell home is different from termux home or shared. The rc files are usually unique for different shells.

  • If the homes are different, then sudo shells and termux shells will have different rc files, stored in their own homes.

  • If the homes are shared and the shell has no --rc param or environmental variable for rc files, then sudo shells and termux shells will have to share the same RCFILE, implied by (shared) and (hard-coded) (by the shell) columns, otherwise will be different.

For shells that do not have rc files have their columns set to -.

Shell RCFILE (different home) RCFILE (shared home) Set Method
bash .bashrc .sudo_bashrc --rcfile
zsh .zshrc (shared) $ZDOTDIR
dash .dashrc .sudo_dashrc $ENV
sh .shrc .sudo_shrc $ENV
fish .config/fish/config.fish (shared) $XDG_CONFIG_HOME
python .pythonrc .sudo_pythonrc $PYTHONSTARTUP
ruby .irbrc (shared) (hard-coded)
pry .pryrc (shared) (hard-coded)
node - - -
perl - - -
lua5.2 - - -
lua5.3 - - -
lua5.4 - - -
php php.ini .sudo_php.ini -c
python2 .python2rc .sudo_python2rc $PYTHONSTARTUP
ksh .kshrc .sudo_kshrc $ENV

The rc file parent directory is automatically created when sudo command is run if it does not exist. The root:root ownership and 700 permission is also set to it.

The rc file is automatically created when sudo command is run if it does not exist. The root:root ownership and 600 permission is also set to it.

The rc file parent directory and rc file will not be created automatically if -no-create-rc is passed.

Shell History Files

The following shell history files are used for different shells depending on if sudo shell or sudo post shell home is different from termux home or shared. The history files are usually unique for different shells.

  • If the homes are different, then sudo shells and termux shells will have different history files, stored in their own homes.

  • If the homes are shared and the shell has no environmental variable for history files, then sudo shells and termux shells will have to share the same HISTFILE, implied by (shared) and (hard-coded) (by the shell) columns, otherwise will be different.

For shells that do not have history files have their columns set to -. For shells whose history cannot be disabled have their Disable Method column set to (not possible).

For pry shell, the existing history will still be loaded, but new history will not be saved.

Shell HISTFILE (different home) HISTFILE (shared home) Set Method Disable Method
bash .bash_history .sudo_bash_history $HISTFILE HISTFILE="/dev/null"
zsh .zsh_history .sudo_zsh_history $HISTFILE HISTFILE="/dev/null"
dash .dash_history .sudo_dash_history $HISTFILE HISTFILE="/dev/null"
sh .sh_history .sudo_sh_history $HISTFILE HISTFILE="/dev/null"
fish .local/share/fish/fish_history .local/share/fish/sudo_fish_history $fish_history --private
python .python_history (shared) (hard-coded) readline.write_history_file = *None
ruby .irb_history (shared) (hard-coded) (not possible)
pry .pry_history (shared) (hard-coded) Pry.config.history_save = false
node .node_history .sudo_node_history $NODE_REPL_HISTORY NODE_REPL_HISTORY=""
perl .perl_history .sudo_perl_history rlwrap --history-filename --history-filename "/dev/null"
lua5.2 - - - -
lua5.3 - - - -
lua5.4 - - - -
php .php_history (shared) (hard-coded) (not possible)
python2 - - - -
ksh .ksh_history .sudo_ksh_history $HISTFILE HISTFILE="/dev/null"

The history file parent directory is automatically created when sudo command is run if it does not exist. The root:root ownership and 700 permission is also set to it.

The history file is automatically created when sudo command is run if it does not exist. The root:root ownership and 600 permission is also set to it.

The history file parent directory and history file will not be created automatically if -no-create-hist or --no-hist is passed.

Modifying Default Values

Check the sudo.config file to see the environmental variables that can be used to change the default values. If the sudo.config file exits at ~/.config/sudo/sudo.config, then sudo will automatically source it whenever it is run. It must have termux user ownership or be readable by it.

You can download it from the master branch and set it up by running the following commands. If you are on an older version, you may want to extract it from its release instead.

config_directory="/data/data/com.termux/files/home/.config/sudo"
mkdir -p "$config_directory" && \
chmod 700 -R "$config_directory" && \
curl -L 'https://github.com/agnostic-apollo/sudo/raw/master/sudo.config' -o "$config_directory/sudo.config" && \
chmod 600 "$config_directory/sudo.config"

You can use shell based text editors like nano, vim or emacs to modify the sudo.config file.

nano "/data/data/com.termux/files/home/.config/sudo/sudo.config"

You can also use GUI based text editor android apps that support SAF. Termux provides a Storage Access Framework (SAF) file provider to allow other apps to access its ~/ home directory. However, the $PREFIX/ directory is not accessible to other apps. The QuickEdit or QuickEdit Pro app does support SAF and can handle large files without crashing, however, it is closed source and its pro version without ads is paid. You can also use Acode editor or Turbo Editor if you want an open source app.

Note that the android default SAF Document file picker may not support hidden file or directories like ~/.config which start with a dot ., so if you try to use it to open files for a text editor app, then that directory will not show. You can instead create a symlink for ~/.config at ~/config_sym so that it is shown. Use ln -s "/data/data/com.termux/files/home/.config" "/data/data/com.termux/files/home/config_sym" to create it.

If you use the bash shell in termux terminal session, you can optionally export the environmental variables like $SUDO_SHELL_HOME and $SUDO_POST_SHELL_HOME in the ~/.bashrc file by adding export SUDO_SHELL_HOME="/path/to/home" and export SUDO_POST_SHELL_HOME="/path/to/home" lines to it so that they are automatically set whenever you start a terminal session. However, the ~/.bashrc and rc files of other shells will not be sourced if you are running commands from Termux:Tasker or RUN_COMMAND Intent, and so it is advisable to use the sudo.config file instead, which will be sourced in all cases, regardless of how sudo is run.

Note that $SUDO_SHELL_PS1 and $SUDO_POST_SHELL_PS1 values will not work if $PS1 variable is overridden in rc files in $PREFIX/etc/ or in sudo shell and sudo post shell homes. Check RC File Variables section for more details.

Examples

If you are using a foreground terminal session, then you must disable the bash command completion and history expansion for the current terminal session before running sudo commands to pass multi-line arguments by running bind 'set disable-completion on'; set +H. Otherwise bash will try to auto complete commands and search the history, and you will get prompts like Display all x possibilities? (y or n).

su

  • Drop to an interactive bash shell in superuser (root) context with priority set to termux bin and library paths with the default configuration.

sudo su

  • Drop to an interactive python shell in superuser (root) context with priority set to termux bin and library paths.

sudo --shell=python --work-dir="~/" su

  • Drop to an interactive bash shell in superuser (root) context with priority set to termux bin and library paths with /.suroot directory as sudo shell home and remount to ro disabled before exiting sudo. Since the /.suroot directory is in rootfs / partition, it will automatically be mounted as rw when sudo command is run.

sudo --shell-home="/.suroot" --no-remount-ro su

  • Drop to an interactive bash shell in superuser (root) context with priority set to termux bin and library paths with /.suroot as the shell home and termux home as the working directory. All paths currently in $PATH and $LD_LIBRARY_PATH are also exported.

sudo -LP --shell-home="/.suroot" --work-dir='~/' su

  • Drop to an interactive bash shell in superuser (root) context with priority set to termux bin and library paths, do not store history, export some additional paths in $PATH variable, pass additional options to the bash interactive shell starting including a different rc/init file and run some commands before running the bash shell like exporting some variables and running a script. The value of the --shell-options option is surrounded with double quotes and the --init-file option value passed in it has double quotes escaped to prevent whitespace splitting when its passed to bash. The --shell-pre-commands option is instead surrounded with single quotes as an example and so doesn't need double quotes escaped but will require single quotes in commands to be escaped. Moreover, each command in the --shell-pre-commands option must end with a semicolon ;.

sudo --no-hist --export-paths="/path/to/dir1:/path/to/dir2" --shell-options="--noprofile --init-file \"path/to/file\"" --shell-pre-commands='export VARIABLE_1="VARIABLE_VALUE_1"; export VARIABLE_2="VARIABLE_VALUE_2"; /path/to/script;' su

asu

  • Drop to an interactive bash shell in superuser (root) context with priority set to android bin and library paths with the default configuration.

sudo asu

path

  • Run top command to show top 10 processes of any user.

sudo top -m 10 -n 1

  • Run ps command to processes of all users.

sudo ps -ef

  • Run android dumpsys command.

sudo dumpsys

  • Run android dumpsys command and filter output to show only termux related entires.

sudo dumpsys | grep termux

script

bash
  • Pass a bash script text surrounded with single quotes that prints the first 2 args to stdout. There is normally no need to pass --shell=bash since bash shell would be the default shell.
sudo -s 'echo "Hi, $1 $2."' "bash" "shell"
  • Pass a bash script text surrounded with single quotes that prints the first 2 args to stdout and start an interactive bash shell.
sudo -si 'echo "Hi, $1 $2."' "bash" "shell"
  • Pass a bash script text surrounded with single quotes that prints the first 2 args to stdout and start an interactive bash shell. The script is forcefully stored in a temp file named sudo_test in a temp directory $HOME/.sudo.temp.XXXXXX, which is also not deleted after sudo exits. The title of the terminal session is also set to sudo_test.
sudo -sif --keep-temp --script-name="sudo_test" --title="sudo_test" 'echo "Hi, $1 $2."' "bash" "shell"
  • Pass a path to bash script file to the bash shell instead of script text, with 2 args and start an interactive bash shell.
sudo -siF '~/.termux/tasker/termux_tasker_basic_bash_test' "bash" "shell"
  • Pass a bash script text surrounded with single quotes that prints the first 2 args to stdout and run some commands before running the script like exporting some variables. The --shell-pre-commands option is surrounded with single quotes and so doesn't need double quotes escaped but will require single quotes in commands to be escaped. Moreover, complex commands can be passed as argument to the --shell-pre-commands option, which optionally may not end with a semicolon ;.
sudo -s --shell-pre-commands='
export VARIABLE_1="VARIABLE_VALUE_1"
export VARIABLE_2="VARIABLE_VALUE_2"
' '
echo "Hi, $1 $2."
echo "VARIABLE_1=\`$VARIABLE_1\`"
echo "VARIABLE_2=\`$VARIABLE_2\`"
' "bash" "shell"
  • Pass a bash script text surrounded with single quotes that prints the first 2 args to stdoutand start an interactive python shell and run some commands before running the script, after running the script but before going to launcher activity, and after going to launcher activity but before starting the interactive python shell.
sudo -sil --post-shell="python" --shell-pre-commands='echo "Running script"' --shell-post-commands='echo "Script complete\nGoing to launcher"' --shell-pre-commands='echo "Starting interactive python shell"' 'echo "Hi, $1 $2."' "bash" "shell"
  • Pass a bash script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=bash <(cat <<'SUDO_EOF'
echo 'What is your name?'
read name
echo "Hi, $name."
SUDO_EOF
)
  • Pass a bash script text surrounded with single quotes that reads a name from stdin and prints it to stdout.
sudo -s --shell=bash '
echo "What is your name?"
read name
echo "Hi, $name."
'
  • Pass a bash script text surrounded with single quotes that reads a name from stdin and prints it to stdout, where the script itself also contains single quotes.
sudo -s --shell=bash '
echo '\''What is your name?'\''
read name
echo "Hi, $name."
'
  • Pass a bash script text with process substitution that prints the first 2 args to stdout and start an interactive shell if only 2 args are received, otherwise exits early with an error without starting the interactive shell afterwards. Additional arguments that will be passed to the core_script are passed to sudo after the process substitution ends.
sudo -sie --shell=bash <(cat <<'SUDO_EOF'
#if parameter count is not 2
if [ $# -ne 2 ]; then
    echo "Invalid parameter count '$#' to 'termux_tasker_basic_bash_test'" 1>&2
    echo "$*" 1>&2
    exit 1
fi

echo "\$1=\`$1\`"
echo "\$2=\`$2\`"

exit 0
SUDO_EOF
) "hello," "termux!"
  • Pass a bash script text surrounded with single quotes that redirects stderr of the core_script to stdout so that both stdout and stderr can be received in a synchronized way as stdout, like in %stdout variable for Termux:Tasker plugin for easier processing of result of commands.
sudo -so 'echo stdout; echo stderr 1>&2'

  

zsh
  • Pass a zsh script text with process substitution that prints the first 2 args to stdout.
sudo -s --shell=zsh <(cat <<'SUDO_EOF'
echo "Hi, $1 $2."
SUDO_EOF
) "zsh" "shell"
  • Pass a zsh script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=zsh <(cat <<'SUDO_EOF'
echo "What is your name?"
read name
echo "Hi, $name."
SUDO_EOF
)

  

fish
  • Pass a fish script text with process substitution that prints the first 2 args to stdout.
sudo -s --shell=fish <(cat <<'SUDO_EOF'
echo "Hi, $argv[1] $argv[2]."
SUDO_EOF
) "fish" "shell"
  • Pass a fish script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=fish <(cat <<'SUDO_EOF'
echo "What is your name?"
read -p "" name
echo "Hi, $name."
SUDO_EOF
)

  

python

Currently, python refers to python3 and python2 refers to python2 in termux. Check Termux Python Wiki for more information.

  • Pass a python script text with process substitution that prints the first 2 args to stdout.
sudo -s --shell=python <(cat <<'SUDO_EOF'
import sys
print("Hi, %s %s." % (sys.argv[1], sys.argv[2]))
SUDO_EOF
) "python" "shell"
  • Pass a python script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=python <(cat <<'SUDO_EOF'
name = input("What is your name?\n")
print("Hi, %s." % name)
SUDO_EOF
)

 

The following "tests" are in solidarity with the youtube-dl devs, EFF and the current Github response of the "incident".

The youtube-dl file is actually not a single python script text file but is a binary file containing multiple python files.

  • Read python script text from a file using cat and pass it with process substitution. Passing the data of the youtube-dl file to sudo script using process substitution will engage automatic base64 encoding of the data and creation of temp script file. The youtube-dl generates its help output based on the named of the its own file, hence --script-name is passed, otherwise help with contain sudo_core_script entries instead. The current size of the youtube-dl binary is over 1MB and so its data cannot be passed as an argument directly (after base64 encoding) since Arguments Data Limits will cross.
sudo -s --shell=python --script-name="youtube-dl" <(cat "$PREFIX/bin/youtube-dl") --help
  • Pass a path to python script file to the python shell instead of script text, with an arg.
sudo -sF --shell=python '$PREFIX/bin/youtube-dl' --help
  • Read python script text from a file using cat in a subshell and pass it as an argument. The script size must not cross Arguments Data Limits. If the script contains binary or non UTF-8 data, then pipe the output of cat to base64 and also pass the --script-decode option.
sudo -s --shell=python "$(cat "$PREFIX/bin/bandcamp-dl")" --help

sudo -s --script-decode --shell=python "$(cat "$PREFIX/bin/bandcamp-dl" | base64)" --help

  

ruby
  • Pass a ruby script text with process substitution that prints the first 2 args to stdout.
sudo -s --shell=ruby <(cat <<'SUDO_EOF'
puts "Hi, " + ARGV[0] + " " + ARGV[1] + "."
SUDO_EOF
) "ruby" "shell"
  • Pass a ruby script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=ruby <(cat <<'SUDO_EOF'
puts "What is your name?"
name = STDIN.gets
name = '' if name.nil?
puts "Hi, " + name.chomp.to_s + "."
SUDO_EOF
)

  

node
  • Pass a node script text with process substitution that prints the first 2 args to stdout.
sudo -s --shell=node <(cat <<'SUDO_EOF'
console.log(`Hi, ${process.argv[2]} ${process.argv[3]}.`)
SUDO_EOF
) "node" "shell"
  • Pass a node script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=node <(cat <<'SUDO_EOF'
const readline = require('readline').createInterface({
    input: process.stdin,
    output: process.stdout
})

readline.question(`What is your name?\n`, (name) => {
    console.log(`Hi, ${name}.`)
    readline.close()
})
SUDO_EOF
)

  

perl
  • Pass a perl script text with process substitution that prints the first 2 args to stdout.
sudo -s --shell=perl <(cat <<'SUDO_EOF'
print "Hi, ", $ARGV[0], " ", $ARGV[1], ".\n";
SUDO_EOF
) "perl" "shell"
  • Pass a perl script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=perl <(cat <<'SUDO_EOF'
print "What is your name?\n";
$name = <STDIN>;
chomp($name);
print "Hi, ", $name, ".\n";
SUDO_EOF
)

  

lua5.2
  • Pass a lua5.2 script text with process substitution that prints the first 2 args to stdout.
sudo -s --shell=lua5.2 <(cat <<'SUDO_EOF'
io.write('Hi, ', arg[1], ' ', arg[2], '.\n')
SUDO_EOF
) "lua5.2" "shell"
  • Pass a lua5.2 script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=lua5.2 <(cat <<'SUDO_EOF'
io.write('What is your name?\n')
local name = io.read()
io.write('Hi, ', name, '.\n')
SUDO_EOF
)

  

lua5.3
  • Pass a lua5.3 script text with process substitution that prints the first 2 args to stdout.
sudo -s --shell=lua5.3 <(cat <<'SUDO_EOF'
io.write('Hi, ', arg[1], ' ', arg[2], '.\n')
SUDO_EOF
) "lua5.3" "shell"
  • Pass a lua5.3 script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=lua5.3 <(cat <<'SUDO_EOF'
io.write('What is your name?\n')
local name = io.read()
io.write('Hi, ', name, '.\n')
SUDO_EOF
)

  

lua5.4
  • Pass a lua5.4 script text with process substitution that prints the first 2 args to stdout.
sudo -s --shell=lua5.4 <(cat <<'SUDO_EOF'
io.write('Hi, ', arg[1], ' ', arg[2], '.\n')
SUDO_EOF
) "lua5.4" "shell"
  • Pass a lua5.4 script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=lua5.4 <(cat <<'SUDO_EOF'
io.write('What is your name?\n')
local name = io.read()
io.write('Hi, ', name, '.\n')
SUDO_EOF
)

  

php
  • Pass a php script text with process substitution that prints the first 2 args to stdout.
sudo -s --shell=php <(cat <<'SUDO_EOF'
<?php
echo "Hi, " . $argv[1] . " " . $argv[2] . ".\n";
SUDO_EOF
) "php" "shell"
  • Pass a php script text with process substitution that reads a name from stdin and prints it to stdout.
sudo -s --shell=php <(cat <<'SUDO_EOF'
<?php
echo "What is your name?\n";
$name = readline();
echo "Hi, " . $name . ".\n";
SUDO_EOF
)

Templates

Tasker

  • Tasks

    • XML
      Download the Termux Tasker Plugin Sudo Templates Task XML and Termux RUN_COMMAND Intent Sudo Templates Task XML files to the android download directory. To download, right-click or hold the Raw button at the top after opening a file link and select Download/Save link or use curl from a termux shell. Then import the downloaded task files into Tasker by long pressing the Task tab button in Tasker home and selecting Import Task.

      curl -L 'https://github.com/agnostic-apollo/sudo/raw/master/templates/plugin_hosts/tasker/Termux_Tasker_Plugin_Sudo_Templates.tsk.xml' -o "/storage/emulated/0/Download/Termux_Tasker_Plugin_Sudo_Templates.tsk.xml"

      curl -L 'https://github.com/agnostic-apollo/sudo/raw/master/templates/plugin_hosts/tasker/Termux_RUN_COMMAND_Intent_Sudo_Templates.tsk.xml' -o "/storage/emulated/0/Download/Termux_RUN_COMMAND_Intent_Sudo_Templates.tsk.xml"

    • Taskernet
      Import Termux Tasker Plugin Sudo Templates Task from Taskernet from here.
      Import Termux RUN_COMMAND Intent Sudo Templates Task from Taskernet from here.

    Check Termux Tasker Plugin Sudo Templates Task Info and Termux RUN_COMMAND Intent Sudo Templates Task Info files for more info on the tasks.

Termux needs to be granted Storage permission to allow it to access /storage/emulated/0/Download directory, otherwise you will get permission denied errors while running commands.

Passing Arguments

The core_script or any other arguments passed for all the command types must be preserved in their original form and must be passed as is to sudo without any variable expansion or history expansion, etc.

This can be done in two ways, either using single quotes to surround the core_script and arguments or passing them with process substitution with a literal cat heredoc.  

If you are using Termux:Tasker plugin to run sudo commands, you would need to use single quotes to pass arguments, since it doesn't support process substitution. You would need to install Termux:Tasker version >= 0.5 since argument parsing is broken in older versions. Check the Passing Arguments Surrounded With Single Quotes section for more details. Check the Template 2 and Template 3 of the Termux Tasker Plugin Sudo Templates Task task for templates on how to use single quotes to pass arguments with Tasker. Basically, just set your script text to the %core_script variable with the Variable Set action and add any additional command options or arguments to the %arguments variable.
 

If you are using a foreground terminal session or scripts to run sudo commands, you can use single quotes to pass arguments or use process substitution. If you are using a foreground terminal session, then you must disable the bash command completion and history expansion for the current terminal session before running sudo command to pass multi-line arguments by running bind 'set disable-completion on'; set +H. Check the Passing Arguments Using Process Substitution section for more details. Check the Examples section for templates on how to use process substitution to pass arguments.  

If you are using RUN_COMMAND Intent to run sudo commands with Tasker using the TermuxCommand() function in Tasker Function action, you don't need to surround the core_script or arguments with single quotes, since arguments are split on a simple comma , instead. If your arguments themselves contain simple commas , (U+002C, &comma;, &#44;, comma), then you must replace them with the comma alternate character ‚ (#U+201A, &sbquo;, &#8218;, single low-9 quotation mark) for each argument separately before passing them to the intent action and would also need to pass the -r command option to sudo. Check the Passing Arguments Using RUN_COMMAND Intent section for more details. Check the Template 2 of the Termux RUN_COMMAND Intent Sudo Templates Task task for a template on how to replace commas in each argument separately with Tasker.  

If you are using RUN_COMMAND Intent to run sudo commands with Tasker or other apps using the am command, like using the Run Shell action in Tasker, you need to surround all your arguments, like the core_script and all other arguments with single quotes when passing them to the com.termux.RUN_COMMAND_ARGUMENTS string array extra after you have escaped all the single quotes in the final value, since otherwise it may result in incorrect quoting if the arguments themselves contain single quotes. However, due to the string array extra, the arguments are still split on a simple comma , so if your arguments themselves contain simple commas , (U+002C, &comma;, &#44;, comma), then you would also have to replace them with the comma alternate character ‚ (#U+201A, &sbquo;, &#8218;, single low-9 quotation mark) for each argument separately before passing them as the argument to the extra and would also need to pass the -r command option to sudo. Check the Passing Arguments Using RUN_COMMAND Intent section for more details. Check the Template 3 of the Termux RUN_COMMAND Intent Sudo Templates Task task for a template on how to replace commas in each argument separately and also escape single quotes in all the arguments with Tasker.  

Note that for RUN_COMMAND Intent, any arguments passed to any command options or the main arguments to sudo should also not be surrounded with single or double quotes to prevent whitespace splitting in the intent action, like done for usage with Termux:Tasker plugin since splitting will occur on simple comma characters instead. Check the Template 4 of the Termux RUN_COMMAND Intent Sudo Templates Task task for a template for this.   

Passing Arguments Surrounded With Single Quotes

Any argument surrounded with single quotes is considered a literal string and variable expansion is not done. However, if an argument itself contains single quotes, then they will need to be escaped properly. You can escape them by replacing all single quotes ' in an argument value with '\'' before passing the argument surrounded with single quotes. So an argument surrounded with single quotes that would have been passed like 'some arg with single quote ' in it' will be passed as 'some arg with single quote '\'' in it'. This is basically 3 parts 'some arg with single quote ', \' and ' in it' but when processed, it will be considered as one single argument with the value some arg with single quote ' in it that is passed to sudo.

For Tasker, you can use the Variable Search Replace action on an %argument variable to escape the single quotes. Set the Search field to one single quote ', and enable Replace Matches toggle, and set Replace With field to one single quote, followed by two backslashes, followed by two single quotes '\\''. The double backslash is to escape the backslash character itself.

Escaping single quotes while running commands in a foreground terminal session will be much harder if there are many single quotes, same would apply for double quote surrounded strings, so use process substitution instead, check below.

The format is the following

sudo -s '
<core_script>
' '[some arg1]' '[some arg2]'

  

Passing Arguments Using Process Substitution

Process Substitution can be used to pass the core_script and core_script_args for the script command type and to pass the command_args for the path command type when running sudo from a foreground terminal session or from a script.

The following is the format for passing core_script text.

sudo -s <(cat <<'SUDO_EOF'
<core_script>
SUDO_EOF
)

The following is the process substitution part

<(

)

Inside it there is a cat Here Document. The script text should start after a newline after the 'SUDO_EOF' part. You can type anything as script text other than SUDO_EOF which when read, ends the script. The ending SUDO_EOF should be alone on a separate line. The starting 'SUDO_EOF' is surrounded with single quotes so that script is considered a literal string and variable expansion, etc doesn't happen.

cat <<'SUDO_EOF'

SUDO_EOF

Basically any text you type inside the cat heredoc will be passed to the process substitution which will create a temporary file descriptor for it in /proc/self/fd/<n> and pass the path to sudo script so that it can read the argument text from it.

You can also read text from an existing script file using cat and pass that to sudo like the following

sudo -s <(cat "~/some-script")

  

Passing Arguments Using RUN_COMMAND Intent

To use RUN_COMMAND Intent that has arguments working properly, you need to install Termux version >= 0.100 and Tasker version >= 5.9.4.beta. However, leading and trailing whitespaces from arguments will be removed for Tasker version < 5.11.1.beta if you are using TermuxCommand() function, so its advisable to use a higher version or use am command instead.  

If you are using the am command, the format is am startservice --user 0 -n com.termux/com.termux.app.RunCommandService -a com.termux.RUN_COMMAND --es com.termux.RUN_COMMAND_PATH '<path>' --esa com.termux.RUN_COMMAND_ARGUMENTS '<one_or_more_args_seperated_with_commas>' --es com.termux.RUN_COMMAND_WORKDIR '/data/data/com.termux/files/home' --ez com.termux.RUN_COMMAND_BACKGROUND 'false'  

If you are using the TermuxCommand() function, the format is TermuxCommand(path,<one_or_more_args_seperated_with_commas>,workdir,background). The args can be of any count, each separated with a simple comma ,. The only condition is that in the list the first must be path and the last two must be workdir and background respectively.  

For both the --esa com.termux.RUN_COMMAND_ARGUMENTS string array extra and the TermuxCommand() function, if you want to pass an argument that itself contains a simple comma , (U+002C, &comma;, &#44;, comma), it must be escaped with a backslash \, so that the argument isn't split into multiple arguments. The only problem is that, the arguments received by the script being executed will contain \, instead of , since the reversal isn't done as described in the am command source while converting to a string array. Tasker uses the same method. There is also no way for the am command or the script to know whether \, was done to prevent arguments splitting or \, was a literal string naturally part of the argument.

// Split on commas unless they are preceeded by an escape.
// The escape character must be escaped for the string and
// again for the regex, thus four escape characters become one.
String[] strings = value.split("(?<!\\\\),");
intent.putExtra(key, strings);

 

sudo uses an alternative method to handle such conditions. If an argument contains a simple comma ,, then instead of escaping them with a backslash \,, replace all simple commas with the comma alternate character ‚ (#U+201A, &sbquo;, &#8218;, single low-9 quotation mark). This way argument splitting will not be done. You can pass the -r option to sudo which will then parse arguments as per RUN_COMMAND intent rules to replace all the comma alternate characters back to simple commas. It would be unlikely for the core_script or the arguments to naturally contain the comma alternate characters for this to be a problem. Even if they do, they might not be significant for any script logic. If they are, then you can set a different character that should be replaced, with the --comma-alternative option. The -r and --comma-alternative options should ideally be the first options passed so that sudo replaces the alternative comma characters from all arguments passed after the options.

For Tasker use the Variable Search Replace action on an %argument variable to replace the simple comma characters. Set the Search field to one simple comma ,, and enable Replace Matches toggle, and set Replace With field to %comma_alternative where the %comma_alternative variable must contain the comma alternate character ‚.

Issues

Automatic redirection of stderr to stdout in SuperSU

In SuperSU v2.82 for the script command type, if stdin is available like running su in an interactive shell like from a foreground terminal session, then it automatically redirects stderr of commands to stdout, specially affecting the --script-redirect and related command options. However, if commands are run in a non-interactive shell, in the background, like from Termux:Tasker plugin, then stdout and stderr streams behave normally and are separate. This can be confirmed by running (su -c 'echo 1 1>&2' 2>/dev/null) and (exec <&-; su -c 'echo 1 1>&2' 2>/dev/null) in a terminal session. In the former case, 1 is still printed on the screen even though stderr is redirected to /dev/null. The later case closes the stdin file descriptor which makes su assume its running non-interactively. Running (su -c 'echo 1 1>&2' 1>/dev/null) also suppresses printing since it redirects stdout to /dev/null instead. Running (bash -c 'echo 1 1>&2' 2>/dev/null) works normally. Reopening stdin with hacks, inside the su shell doesn't work either for a few reasons, including that stderr redirection to stdout starts happening again. This seems to be an issue of the libsuperuser itself or how the su binary handles streams internally and might not be solvable but if you have a solution that can be used to prevent automatic redirection, please report it.

This does not affect usage with Termux:Tasker in background mode. This does not apply to Magisk, at least the currently latest version v21.1. However, this may apply to other su implementation.   

su -c support

The sudo script requires the -c command option support by the su binary. The su that comes with the android studio avd does not support it. Other su implementations may not support it either.

Moreover, linux distros removed support for starting interactive shells with the su -c command. Check debian su manpage. The -c command option info specifies that The executed command will have no controlling terminal. This option cannot be used to execute interactive programs which need a controlling TTY.. For more info, check debian bug report #628843 and ubuntu CVE-2005-4890. However, this likely does not apply to android su implementations, at least does not apply for SuperSU and Magisk currently, so sudo should work fine, at least on those.

Worthy Of Note

RC File Variables

If you don't know what $PATH, $LD_LIBRARY_PATH and $PS1 variables or rc files are or don't care to find out, then just run the commands below so that sudo works properly, otherwise read the details below. Ignore No such file or directory errors when running the commands.

sed -i'' -E 's/^(PS1=.*)$/\(\[ -z "\$PS1" \] \|\| \[\[ "\$PS1" == '\''\\s-\\v\\\$ '\'' \]\]\) \&\& \1/' "/data/data/com.termux/files/usr/etc/bash.bashrc"
sed -i'' -E 's/^(PS1=.*)$/\(\[ -z "\$PS1" \] \|\| \[\[ "\$PS1" == '\''%m%# '\'' \]\]\) \&\& \1/' "/data/data/com.termux/files/usr/etc/zshrc"
su -c "rm \"/data/data/com.termux/files/home/.suroot/.bashrc\""

 

rc files, short for run commands, are shell specific files that are run or sourced whenever an interactive shell is started to define variables and functions etc.

Make sure in your rc files like ~/.suroot/.bashrc file for bash (where ~/.suroot is the sudo shell home), the $PATH, $LD_LIBRARY_PATH and $PS1 variables and any other variables exported by sudo are not overridden, otherwise the sudo commands will not work properly, since sudo exports its own custom variable values which will get overridden when rc files are sourced by any new shell started. You can run commands like sudo -v --dry-run --shell=bash su to see what variables are normally exported for a given shell by sudo.  

$PATH or $LD_LIBRARY_PATH

Check the PATH and LD_LIBRARY_PATH Priorities section for more info on what these variables are.

For the $PATH or $LD_LIBRARY_PATH variables, either remove their variable set lines completely or if necessary only append any required paths to the existing variable values like export PATH="$PATH:/dir1:/dir2" and export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/dir1:/dir2" instead of overriding them with export PATH="/dir1:/dir2" and export LD_LIBRARY_PATH="/dir1:/dir2" in your rc files.  

$PS1

The $PS1 variable, short for Prompt String 1, defines the characters you see at the start of the "line" when typing commands in shells running interactively like bash or zsh. For termux bash shell, this defaults to $ . For termux zsh shell, this defaults to % .

If you want to allow sudo to set its own default $PS1 value # or the one set with the $SUDO_SHELL_PS1 or $SUDO_POST_SHELL_PS1 variables in the sudo.config file, then make sure the $PS1 value is not overridden by the shell rc files, otherwise you will not be able to easily tell the difference between whether you are running a shell via sudo or normally as the termux user when you run commands like sudo su. You can however check the value of $SHLVL to see the nested shell level, run printenv | grep SHLVL.

  1. The rc files in $PREFIX/etc/ are sourced first whenever shells are started by sudo. The $PS1 value is set and exported by sudo before new shells are started, however, the value will get replaced if its overridden by the rc files when they are sourced during startup of the new shell.

    • bash shell currently uses the $PREFIX/etc/bash.bashrc file, in which it sets the default value of $PS1 to \$ or \[\e[0;32m\]\w\[\e[0m\] \[\e[0;97m\]\$\[\e[0m\] in recent versions. You need to replace the line PS1='\$ ' or PS1=<default> with the conditional ([[ -z "$PS1" ]] || [[ "$PS1" == '\s-\v\$ ' ]]) && PS1=<default> so that $PS1 is only set if its not already set or is set to the default value internally used by bash. You can run the command sed -i'' -E 's/^(PS1=.*)$/\(\[ -z "\$PS1" \] \|\| \[\[ "\$PS1" == '\''\\s-\\v\\\$ '\'' \]\]\) \&\& \1/' "/data/data/com.termux/files/usr/etc/bash.bashrc" to automatically do it or you can do it manually by running nano "/data/data/com.termux/files/usr/etc/bash.bashrc".

    • zsh shell currently uses the $PREFIX/etc/zshrc file, in which it sets the default value of $PS1 to %# . You need to replace the line PS1='%# ' or PS1=<default> with the conditional ([[ -z "$PS1" ]] || [[ "$PS1" == '%m%# ' ]]) && PS1=<default> so that $PS1 is only set if its not already set or is set to the default value internally used by zsh. You can run the command sed -i'' -E 's/^(PS1=.*)$/\(\[ -z "\$PS1" \] \|\| \[\[ "\$PS1" == '\''%m%# '\'' \]\]\) \&\& \1/' "/data/data/com.termux/files/usr/etc/zshrc" to automatically do it or you can do it manually by running nano "/data/data/com.termux/files/usr/etc/zshrc".

  2. The rc files in ~/.suroot (default sudo shell home) are also sourced afterwards whenever shells are started by sudo. They must also not override the $PS1 value. However, if you want to set a custom value in them for usage outside sudo, then you can add conditionals to override $PS1 only if its not already set or is set to the default termux value set by $PREFIX/etc/* rc files.

    • bash shell default rc file set by sudo is ~/.suroot/.bashrc. You can for example set $PS1 to £ by adding the line ([[ -z "$PS1" ]] || [[ "$PS1" == '\$ ' ]]) && PS1='£ ' to it, where '\$ ' is the default value for PS1 in $PREFIX/etc/bash.bashrc file.

    • zsh shell default rc file set by sudo is ~/.suroot/.zshrc. You can for example set $PS1 to £ by adding the line ([[ -z "$PS1" ]] || [[ "$PS1" == '%# ' ]]) && PS1='£ ' to it, where '%# ' is the default value for PS1 in $PREFIX/etc/zshrc file.

This will ensure that the exported $PS1 variables will not be overridden by rc files for bash and zsh. For other shells that may use the $PS1 variable, you can use similar conditionals in their rc files.  

termux-sudo by st42

If you were previously using termux-sudo by st42, then it would have automatically created the ~/.suroot/.bashrc file with entries like the following. You should either remove those lines if you haven't exported custom values yourself or remove the file entirely if you haven't made changes to it yourself.

export LD_LIBRARY_PATH=$PRE/usr/lib
export PATH=/data/data/com.termux/files/usr/bin:/data/data/com.termux/files/usr/bin/applets:/system/xbin:/system/bin
export PS1="# "

To remove the ~/.suroot/.bashrc file, run su -c "rm \"/data/data/com.termux/files/home/.suroot/.bashrc\"" command.

To edit the ~/.suroot/.bashrc file, run su -c "nano \"/data/data/com.termux/files/home/.suroot/.bashrc\"" command. Make changes as advised above, then press Ctrl+o and then Enter to save and Ctrl+x to exit. You can also open the file with a text editor app with root support like QuickEdit or QuickEdit Pro.   

Arguments and Result Data Limits

There are limits on the arguments size you can pass to commands or the full command string length that can be run, which is likely equal to 131072 bytes or 128KB for an android device defined by ARG_MAX but after subtracting shell environment size, etc, it will roughly be around 120-125KB but limits may vary for different android versions and kernels. You can check the limits for a given termux session by running true | xargs --show-limits. If you exceed the limit, you will get exceptions like Argument list too long. You can manually cross the limit by running something like $PREFIX/bin/echo "$(head -c 131072 < /dev/zero | tr '\0' 'a')" | tr -d 'a', use full path of echo, otherwise the echo shell built-in will be called to which the limit does not apply since exec is not done.

Moreover, exchanging data between Tasker and Termux:Tasker is done using Intents, like sending the command and receiving result of commands in %stdout and %stderr. However, android has limits on the size of actual data that can be sent through intents, it is roughly 500KB on android 7 but may be different for different android versions.

Basically, make sure any data/arguments you pass to sudo script directly on the shell or through scripts or using the Termux:Tasker plugin or RUN_COMMAND Intent intent is less than 120KB (or whatever you found) and any expected result sent back if using the Termux:Tasker plugin is less than 500KB, but best keep it as low as possible for greater portability. If you want to exchange an even larger data between tasker and termux, use physical files instead.

The argument data limits also apply for the RUN_COMMAND Intent intent.   

PATH and LD_LIBRARY_PATH Priorities

The word executable will be used henceforth for binaries, scripts and any other executable files.

Termux executables currently exist at /data/data/com.termux/files/usr/bin and /data/data/com.termux/files/usr/bin/applets Termux libraries exist at /data/data/com.termux/files/usr/lib.

Android executables normally exist at /system/bin and/or /system/xbin Android libraries exist at /system/lib and/or /system/lib64.

When sudo su commands is run, then the termux executables paths are prepended to android executables paths in the $PATH variable. The termux library paths are prepended to android library paths in the $LD_LIBRARY_PATH variable. This gives priority to termux paths.

When sudo asu commands is run, then the android executables paths are prepended to termux executables paths in the $PATH variable. The android library paths are prepended to termux library paths in the $LD_LIBRARY_PATH variable. This gives priority to android paths.

The $PATH variable sets the paths to search for executables when commands are executed. The $LD_LIBRARY_PATH variable sets the paths to search for libraries for dynamic linking required by the commands that are executed. The path that appears first in both the variables is searched first and if the required binary, executable or library is found, that is the one thats used without looking further.  

There are a few important things to consider when using sudo with termux.

A executable that you want to run may exist in both termux and android executable paths but you may want to run a specific one. If you want to run the termux one instead of the the android one then run sudo su command and then run the command to run the executable. If you want to run the android one instead of the the termux one then run sudo asu command and then run the command to run the executable. However in both cases, if you write the absolute path of the executable instead of just writing its basename, the executable at the path you wrote will be executed even if the other ones path exist before in the $PATH variable.

Another thing to consider is that dynamic library linking errors may occur when executables try to link to the wrong library. Executables should be linked with libraries they are compatible with and that define all the needed functions needed by the executable. Executables that exist in termux executable path should ideally be linked with libraries that exist in termux library path. Executables that exist in android executable path should ideally be linked with libraries that exist in android library path.

When an executable is run, the paths in the $LD_LIBRARY_PATH variable are searched for the library that is required and whichever matching library is found first is used, even if that library is not compatible with the executable. If the library is indeed incompatible a linking error occurs with errors that may include words like CANNOT LINK EXECUTABLE and cannot locate symbol some_symbol referenced by /lib.....

So if an executable in android executable path tries to link with a library in termux library paths to which it is incompatible with, then a linking error will occur. This is likely to happen with some executables including the android dumpsys or input binaries among others. A linking error may occur the other way around too, when a termux executable tries to link with libraries in android library path. To prevent these linking error from occurring in most situations, separate sudo su and sudo asu commands exist, which set the correct order of paths in the $PATH and $LD_LIBRARY_PATH variables so that normally termux executables are linked with termux libraries and android executables are linked with android libraries whenever either command is run.  

However, another way to automatically prioritize android libraries is by running the path command type with sudo <command>. If the command exists in the /system partition, then android library paths are prepended to termux library paths in the $LD_LIBRARY_PATH variable automatically. An absolute path is not needed to be passed for this to work as the $PATH_TO_EXPORT is automatically searched. This is helpful for situations when you are already in a sudo su shell and do not want to shift to the sudo asu shell or unset $LD_LIBRARY_PATH to run just one executable in android executables paths.

You can also use the tpath and apath functions if they are defined in the rc file of your interactive shell to shift priorities.

Normally sudo su will work fine without problem when dropping to sudo shell. But if you want to specifically run an executable in the android executable paths instead of the one in termux executable paths or are getting linking errors when running android executables with sudo su, then try using sudo asu and then running the required command or use sudo <command> or sudo -a <command>.

tpath and apath functions

For the shells bash zsh dash sh fish ksh, additional functions named tpath and apath are added to their rc files if the sudo script creates the rc files, they are not added otherwise. You can call these functions to set priorities from inside interactive shell sessions only when running sudo su, sudo asu or sudo -is <core_script commands, since they depend on some environmental variables set by the sudo script and are not hard-coded in case of future changes.

The tpath function will set priority to termux bin and library paths in $PATH and $LD_LIBRARY_PATH variables.

The apath function will set priority to android bin and library paths in $PATH and $LD_LIBRARY_PATH variables.

The functions allows the users to quickly switch priorities without having to switch between sudo su and sudo asu shells.

If you already have an existing rc file for your shell like ~/.suroot/.bashrc and want to add the functions to it. Just temporarily move (not copy) the file to somewhere else and run sudo su command with the optional --shell option, then copy the functions from the new rc file created by sudo to your old file, then remove the new file and move the old file back.

export and unset functions

For the fish shell, additional functions named export and unset are also added to the rc files if the sudo script creates its rc file, they are not added otherwise. The functions port the bash export var=value and unset var functionality respectively.

Tests

Check the sudo_tests script to run automated tests for the sudo script command types, options and shells. Usage instructions are inside the script. There are more examples for running sudo inside the sudo_tests script that can be used by users, although may not be too user friendly to view or understand.

FAQs And FUQs

Check FAQs_And_FUQs.md file for the Frequently Asked Questions(FAQs) and Frequently Unasked Questions(FUQs).

Changelog

Check CHANGELOG.md file for the Changelog.

Contributions

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About

A wrapper script to drop to the supported shells or execute shell script files or their text passed as an argument with superuser (root) context in termux

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bash tasker termux termux-tasker

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Apr 10, 2021
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