42SH

42sh is one of the final branch's project in the 42 cursus, whose goal was to implement a shell, our ability to contribute to a big project in a group has also been tested.

We deviated from a base of mine but the final project was the result of the contribution of Jeremi Raymond, Sebastien Le Rest, Gaetan Dufay and me Mohammed Merabet, we each worked on different aspect of the project but my main duty was to make all the abstraction and the genericity of a system that should simplify the addition of new features.

Thanks to that abstraction, it was easier to get the project at its full potential. For example adding features that were not mandatory, such as shell scripting and job control.

Thanks to our hard work we got a final grade of 121 !

Features

Mandatory part

• Prompt display.
• Command line edition.
• Bultins: cd, env, setenv, unsetenv, echo and exit.
• Executing commands from the PATH environnement variable.
• The logical operators && and ||.
• The ; separator.

Optional part

• Inhibitors " (double quotes), ' (simple quotes) and \ (backslash).
• Heredoc << and file descriptor aggregations.
• Globbing : *, ?, [], {}, etc.
• Command substitution `` and $().
• Subshells (command list) and command groups { command list }.
• Local variables and unset, set, export builtins.
• history builtin, (the ! feature is not handled).
• A complete line edition (i.e the ability to edit a line with various keyboard shortcut).
• The builtin read.
• Dynamic autocompletion.

Very very much appreciated in the grading

• Job control with the jobs, fg, and bg buitlins and the & operator.
• Shell script.

Additional features

• Arithmetic expansions $((...)) and $[...].
• Positional argument expansion $0, $1 ... and $@.
• The PROMPT environnement variable to change the prompt in real time.
• Functions with the := operator func_name := { command list }.
• if and while keyword if command then command or if command then { command list } or even if { command list } then { command list }.
• The .42shrc file in the home directory, that is executed at the beginning of the shell.
• -c option to give a command in parameter ./42sh -c 'echo Hello World'.

Core Team

• Jeremi Raymond, (The rigorous)
• Sebastien Le Rest, (The bug finder)
• Gaetan Dufay, (The stagiaire)
• Mohammed Merabet, (The genius and The modest)

**FINAL GRADE: 121**