The existence of shells is linked to the very existence of IT. At the time, all developers agreed that communicating with a computer using aligned 1/0 switches was seriously irritating. It was only logical that they came up with the idea of creating a software to communicate with a computer using interactive lines of commands in a language somewhat close to the human language. Thanks to Minishell, you’ll be able to travel through time and come back to problems people faced when Windows didn’t exist.
Program should (and actually do):
- Display a prompt when waiting for a new command.
- Have a working history.
- Search and launch the right executable (based on the PATH variable or using a relative or an absolute path).
- Not use more than one global variable.
- Single quote ’ prevents the shell from interpreting the metacharacters in the quoted sequence.
- Double quote " prevents the shell from interpreting the metacharacters in the quoted sequence except for $ (dollar sign).
- Redirections:
- < redirects input.
- > redirects output.
- << should be given a delimiter, then read the input until a line containing the delimiter is seen.
- >> redirects output in append mode.
- Pipes (| character). The output of each command in the pipeline is connected to the input of the next command via a pipe.
- Environment variables ($ followed by a sequence of characters) which expands to their values.
- $? expands to the exit status of the most recently executed foreground pipeline.
- ctrl-C, ctrl-D and ctrl-\ behaves like in bash.
- In interactive mode:
- ctrl-C displays a new prompt on a new line.
- ctrl-D exits the shell.
- ctrl-\ does nothing.
- Builtins:
- echo with option -n
- cd with only a relative or absolute path
- pwd with no options
- export with no options
- unset with no options
- env with no options or arguments
- exit with no options
- && and || for priorities.
- Wildcards * working for the current working directory.
