Description

Minishell is an operating system shell, providing a complete command line interface for the system. REPL-based command interpreter features lexical parsing, command tokenization, and execution. Written in C programming language from scratch with a self implemented C library (libft) using Unix system calls. Handled core process management using Unix system calls (fork, exec, wait), enabling execution of both builtin and external programs.

Main Features

• Pipeline execution (|)
• I/O redirections (>, <, >>)
• Multi-process command chaining
• Environment variable expansion and
• Runtime modification of shell state
• Builtin shell commands (e.g., cd, exit, export)

Code formatting

Code was formatted in compliance with the Norm.

This is a highly unconventional format and does not reflect our own preference.

Some key rules of the format:

• All source files must have the "42 header".
• Strict 80 column limit for all lines.
• Functions have a strict 25 line limit.
• Variables must be declared at the top of the functions (like C89 style).
• Functions can define at most 5 variables.
• No empty lines allowed inside the function body except right after the variable declaration.
• No comments allowed inside the function body.
• Functions can have at most 4 parameters.
• Maximum of 5 functions per file.

Examples

• Redirections

  • Input <

    • Basic input

       cat < file.txt
      

    • Non-existent file

       cat < does_not_exist.txt
      

    • Input + args

       wc -l < file.txt
      

  • Output >

    • Basic overwrite

       echo hello > out.txt
       cat out.txt
      

    • Overwrite existing file

       echo first > out.txt
       echo second > out.txt
       cat out.txt
      

    • Command + output

       ls > out.txt
      

  • Append >>

    • Basic append

       echo a >> out.txt
       echo b >> out.txt
       cat out.txt
      

    • Mix overwrite + append

       echo start > out.txt
       echo middle >> out.txt
       echo end >> out.txt
       cat out.txt
      

  • Heredoc <<

    • Basic heredoc

       cat << EOF
       hello
       world
       EOF
      

    • Empty heredoc

       cat << EOF
       EOF
      

    • Multiple lines

       cat << STOP
       one
       two
       three
       STOP
      

  • Edge / bug-detection tests

    • No space cases

       echo hi>file.txt
       cat<file.txt
      

    • Multiple redirections

       echo hello > a.txt > b.txt
      

    • Mixed input/output

       wc -l < file.txt > out.txt