commands.md

Linux Commands Cheat Sheet

The command line terminal in Linux is the operating system’s most powerful component. However, due to the sheer amount of commands available, it can be intimidating for newcomers. Even longtime users may forget a command every once in a while and that is why we have created this Linux cheat sheet commands guide.

In this page, we’ll present you with a curated list of the most handy Linux commands.

Please note that those commands are for Linux in general, both RedHat-like and Debian-like distributions. There are some commands in the Package management session which may be specific for Redhat-based such as yum and rpm which do not work in Ubuntu (Debian-based).

File Commands

Command	Description
ls	List files in the directory
ls -a	List all files (shows hidden files)
locate [name]	Find all files and directories related to a particular name:
pwd	Show directory you are currently working in
mkdir [directory]	Create a new directory
rm [file_name]	Remove a file
rm -r [directory_name]	Remove a directory recursively
rm -rf [directory_name]	Recursively remove a directory without requiring confirmation
cp [file_name1] [file_name2]	Copy the contents of one file to another file
cp -r [directory_name1] [directory_name2]	Recursively copy the contents of one file to a second file
mv [file_name1] [file_name2]	Rename [file_name1] to [file_name2] with the command
ln -s /path/to/[file_name] [link_name]	Create a symbolic link to a file
touch [file_name]	Create a new file using touch
more [file_name]	Show the contents of a file
cat [file_name]	or use the cat command
cat [file_name1] >> [file_name2]	Append file contents to another file
head [file_name]	Display the first 10 lines of a file with head command
tail [file_name]	Show the last 10 lines of a file
wc	Show the number of words, lines, and bytes in a file using wc
ls | xargs wc	List number of lines/words/characters in each file in a directory with the xargs command
cut -d[delimiter] [filename]	Cut a section of a file and print the result to standard output
[data] | cut -d[delimiter]	Cut a section of piped data and print the result to standard output
awk '[pattern] {print $0}' [filename]	Print all lines matching a pattern in a file
diff [file1] [file2]	Compare two files and display differences
source [filename]	Read and execute the file content in the current shell
[command] | tee [filename] >/dev/null	Store the command output in a file and skip the terminal output

Searching

Command	Description
grep [pattern] [file_name]	Search for a specific pattern in a file with grep
grep -r [pattern] [directory_name]	Recursively search for a pattern in a directory:
locate [name]	Find all files and directories related to a particular name:
find [/folder/location] -name [a]	List names that begin with a specified character [a] in a specified location [/folder/location] by using the find command:
find [/folder/location] -size [+100M]	See files larger than a specified size [+100M] in a folder:

Directory Navigation

Command	Description
tar cf [compressed_file.tar] [file_name]	Archive an existing file
tar xf [compressed_file.tar]	Extract an archived file
tar czf [compressed_file.tar.gz]	Create a gzip compressed tar file by running
gzip [file_name]	Compress a file with the .gz extension

File Transfer

Command	Description
scp [file_name.txt] [server/tmp]	Copy a file to a server directory securely using the Linux scp command
rsync -a [/your/directory] [/backup/]	Synchronize the contents of a directory with a backup directory using the rsync command

Users and Groups

Command	Description
id	See details about the active users
last	Show last system logins
who	Display who is currently logged into the system with the who command
w	Show which users are logged in and their activity
groupadd [group_name]	Add a new group by typing
adduser [user_name]	Add a new user
usermod -aG [group_name] [user_name]	Add a user to a group
sudo [command_to_be_executed_as_superuser]	Temporarily elevate user privileges to superuser or root using the sudo command
userdel [user_name]	Delete a user
usermod	Modify user information with
chgrp [group-name] [directory-name]	Change directory group

Package management

Command	Description
yum list installed	List all installed packages with yum
yum search [keyword]	Find a package by a related keyword
yum info [package_name]	Show package information and summary
yum install [package_name.rpm]	Install a package using the YUM package manager
dnf install [package_name.rpm]	Install a package using the DNF package manager
apt install [package_name]	Install a package using the APT package manager
rpm -i [package_name.rpm]	Install an .rpm package from a local file
rpm -e [package_name.rpm]	Remove an .rpm package
dpkg -i [package_name.deb]	Install an .deb package from a local file
dpkg -r [package_name.deb]	Remove an .deb package
tar zxvf [source_code.tar.gz] && cd [source_code] && ./configure && make && make install	Install software from source code

Process management

Command	Description
ps	See a snapshot of active processes
pstree	Show processes in a tree-like diagram
pmap	Display a memory usage map of processes
top	See all running processes
kill [process_id]	Terminate a Linux process under a given ID
pkill [proc_name]	Terminate a process under a specific name
killall [proc_name	Terminate all processes labelled “proc”
bg	List and resume stopped jobs in the background
fg	Bring the most recently suspended job to the foreground
fg [job]	Bring a particular job to the foreground
lsof	List files opened by running processes
trap "[commands-to-execute-on-trapping]" [signal]	Catch a system error signal in a shell script
wait	Pause terminal or a Bash script until a running process is completed
nohup [command] &	Run a Linux process in the background

System Management and Information

Command	Description
uname -r	Show system information
uname -a	See kernel release information
uptime	Display how long the system has been running, including load average
hostname	See system hostname
hostname -i	Show the IP address of the system
last reboot	List system reboot history
date	See current time and date
timedatectl	Query and change the system clock with
cal	Show current calendar (month and day)
whoami	See which user you are using
finger [username]	Show information about a particular user
ulimit [flags] [limit]	View or limit system resource amounts
shutdown [hh:mm]	Schedule a system shutdown
shutdown now	Shut Down the system immediately

Disk Usage

Command	Description
df -h	See free and used space on mounted systems
df -i	Show free inodes on mounted filesystems
fdisk -l	Display disk partitions, sizes, and types with the command
du -ah	See disk usage for all files and directory
du -sh	Show disk usage of the directory you are currently in
findmnt	Display target mount point for all filesystem
mount [device_path] [mount_point]	Mount a device

SSH Login

Command	Description
ssh user@host	Connect to host as user
ssh host	Securely connect to host via SSH default port 22
ssh -p [port] user@host	Connect to host using a particular port

File Permission

Command	Description
chmod 777 [file_name]	Assign read, write, and execute permission to everyone
chmod 755 [file_name]	Give read, write, and execute permission to owner, and read and execute permission to group and others
chmod 766 [file_name]	Assign full permission to owner, and read and write permission to group and others
chown [user] [file_name]	Change the ownership of a file
chown [user]:[group] [file_name]	Change the owner and group ownership of a file

Network

Command	Description
ip addr show	List IP addresses and network interfaces
ip address add [IP_address]	Assign an IP address to interface eth0
ifconfig	Display IP addresses of all network interfaces with
netstat -pnltu	See active (listening) ports with the netstat command
netstat -nutlp	Show tcp and udp ports and their programs
whois [domain]	Display more information about a domain
dig [domain]	Show DNS information about a domain using the dig command
dig -x host	Do a reverse lookup on domain
dig -x [ip_address]	Do reverse lookup of an IP address
host [domain]	Perform an IP lookup for a domain
hostname -I	Show the local IP address
wget [file_name]	Download a file from a domain using the wget command
nslookup [domain-name]	Receive information about an internet domain
curl -O [file-url]	Save a remote file to your system using the filename that corresponds to the filename on the server

Variables

Command	Description
let "[variable]=[value]"	Assign an integer value to a variable
export [variable-name]	Export a Bash variable
declare [variable-name]= "[value]"	Declare a Bash variable
set	List the names of all the shell variables and functions
echo $[variable-name]	Display the value of a variable

Shell Command Management

Command	Description
alias [alias-name]='[command]'	Create an alias for a command
watch -n [interval-in-seconds] [command]	Set a custom interval to run a user-defined command
sleep [time-interval] && [command]	Postpone the execution of a command
at [hh:mm]	Create a job to be executed at a certain time (Ctrl+D to exit prompt after you type in the command)
man [command]	Display a built-in manual for a command
history	Print the history of the commands you used in the terminal

Linux Keyboard Shortcuts

Command	Description
Ctrl + C	Kill process running in the terminal
Ctrl + Z	Stop current process - The process can be resumed in the foreground with fg or in the background with bg
Ctrl + W	Cut one word before the cursor and add it to clipboard
Ctrl + U	Cut part of the line before the cursor and add it to clipboard
Ctrl + K	Cut part of the line after the cursor and add it to clipboard
Ctrl + Y	Paste from clipboard
Ctrl + R	Recall last command that matches the provided characters
Ctrl + O	Run the previously recalled command
Ctrl + G	Exit command history without running a command
!!	Run the last command again
`Ctrl + D	Log out of current session

Hardware information

Command	Description
dmesg	Show bootup messages
cat /proc/cpuinfo	See CPU information
free -h	Display free and used memory
lshw	List hardware configuration information
lsblk	See information about block devices
lspci -tv	Show PCI devices in a tree-like diagram
dmidecode	Show hardware information from the BIOS
hdparm -i /dev/disk	Display disk data information
hdparm -tT /dev/[device]	Conduct a read-speed test on device/disk
fsck [disk-or-partition-location]	Run a disk check on an unmounted disk or partition