42sh - Advanced Unix Shell

📋 Overview

42sh is a projected made to replicate in C programming language the Unix shell TCSH. The project is carried out by 5 members

🚀 Usage

Basic Usage

./42sh

Launch the shell and start executing commands interactively.

Bonus Features

make bonus
./42sh

The bonus version includes additional features:

• Custom prompt colors: Configurable via .42shrc
• Enhanced alias system: Pre-configured aliases from .42shrc
• Color customization: Use setcolor command to modify prompt colors

Example .42shrc configuration:

alias "lsl=ls -la"
alias "c=clear"
color "YELLOW WHITE BLUE BRIGHT_CYAN"

✨ Some Implemented Features

Basic Features

• Command execution with PATH resolution
• Built-in commands: cd, env, setenv, unsetenv, exit, echo
• Command separators: ; for sequential execution
• Pipes: Multiple pipe chaining (|)
• Redirections: >, >>, <, << (heredoc)
• Error handling: Command not found, permission denied, etc.

Advanced Features

• Globbing: Wildcard expansion (*.c, ?.txt, [abc].c)
• Job control: Background execution (&), jobs, fg, bg
• Aliases: Define and use command aliases
• History: Command history with ! syntax
• Local variables: set and unset commands
• Logical operators: && and || (partial support)
• Backticks: Command substitution
• Special commands: where, which, repeat
• Parentheses: Command grouping
• Custom getline: Arrow key navigation, history search

Special Variables

• $cwd - Current working directory
• $cwdcmd - Hook executed on directory change
• $precmd - Hook executed before each prompt
• $ignoreeof - Prevent Ctrl-D from exiting
• $term - Terminal type

Inhibitors & Quoting

• Single quotes '...' - Literal strings
• Double quotes "..." - Variable expansion allowed
• Backslash \ - Escape character

🧪 Testing

Run the automated test suite:

make tester
# or
./tester.sh

Run unit tests:

make tests_run

Test Results

Category	Percentage	Tests Passed
basic tests	100%	4/4
path handling	80%	4/5
setenv and unsetenv	100%	2/2
builtin cd	100%	3/3
line formatting (space and tabs)	100%	8/8
error handling	100%	6/6
separator	100%	1/1
simple pipes	100%	3/3
advanced pipes	100%	6/6
redirections	100%	5/5
advanced manipulations	100%	3/3
&& and || tests	100%	3/3
globbing	100%	1/1
var interpreter	100%	3/3
inhibitor	100%	2/2
command substitution (magic quotes)	100%	3/3
alias	75%	3/4
scripting	0%	0/1
foreach	0%	0/1
which	100%	2/2
where	100%	2/2
if	0%	0/2
repeat	100%	1/1
parenthesis	0%	0/1
Overall Results	91.7%	65/72

📚 Keynote result

We got the best 42sh of our class.

Project Mark :

Mark : 25
Automatic tests (11 / 14) :

History (3 / 3.5) :

Job control (2.5 / 2.5) :
Tout les jobs controls
Dynamic command line (0.5 / 2.5) :
pas d'autocomplete

Bonus (5 / 10) :
AST
bashrc
unit test
Questions fun (3 / 5) :

Oral Mark :

Mark : 4444
Testing Policy (4 / 4) :
Tests unitaires, tests fonctionnels

Methodology and Organisation (40 / 40) :
Agilité, github project, pull requests

Involvment (400 / 400) :
Globbings, inhibiteurs, scripting, edit de ligne, système de priorité AST
variable locale, alias
personnalisation, couleurs

Oral Presentation (4000 / 4000) :
Belle uniformité, belle tenue + 1
Attention avec le pointage du doigt
"Merci enzo"
Vous êtes devant la télé mais ça s'est arrangé
Rétrospection
alors attention github n'a pas inventé les branches, c'est git.
Politiques de tests
C'est très fluide.

🔨 Compilation

Standard compilation:

make

Bonus compilation:

make bonus

Clean build files:

make clean      # Remove object files
make fclean     # Remove object files and binary
make re         # Rebuild from scratch

Debug compilation:

make val        # Compile with debug symbols
make runval     # Run with valgrind
make runvalcheck # Run with full memory leak check

Other useful commands:

make run        # Compile and run
make echorun ARG="ls -l" # Test with specific command

💡 Examples

Basic Commands

42sh> ls -l
42sh> cd /tmp
42sh> pwd

Pipes and Redirections

42sh> ls -l | grep .c | wc -l
42sh> cat file.txt > output.txt
42sh> echo "Hello" >> output.txt
42sh> cat < input.txt

Job Control

42sh> sleep 10 &
[1] 12345
42sh> jobs
[1] Running    sleep 10
42sh> fg %1

Aliases

42sh> alias ll ls -la
42sh> ll
42sh> unalias ll

Variables

42sh> set myvar=hello
42sh> echo $myvar
hello
42sh> unset myvar

History

42sh> ls -l
42sh> !-1        # Repeat last command
42sh> !ls        # Repeat last command starting with 'ls'

Special Commands

42sh> which ls
/bin/ls
42sh> where ls cd
cd is a shell built-in
/bin/ls
42sh> repeat 3 echo "Hello"
Hello
Hello
Hello

🐛 Known Issues

• if statements have implementation issues. It has been deactivated in the code for the keynote as it caused crashes

👥 Contributors

• Aryan
• Enzo
• Antony
• Simon
• Jeremy