42-minishell

Score: 100/100

This project is about making a command interpreter (shell) based on bash.

Features

• Built-in commands: cd pwd echo export unset env exit
• Signal handling: CTRL-C CTRL-\ CTRL-D (not quite signal but...)
• Pipes |
• Redirections > < >> <<
• Local variables
• Environment expansions and exit status $?
• Quotes ' "

How It Works

The program has 4 main sections: Splitter -> Lexer -> Parser -> Executor

Let's say our example input is ls -la | wc -l

In Splitter we are dividing input into meaningful parts and store those in a string array (2D char array).

ls
-la
|
wc
-l

In Lexer we are looking at the meaningful parts and determine their type.

ls = COMMAND
-la = ARGUMENT
| = PIPE
wc = COMMAND
-l = ARGUMENT

In Parser we are creating command blocks.

{
  cmd = ls
  args = [-la]
  in = stdin
  out = pipe
}
{
  cmd = wc
  args = [-l]
  in = pipe
  out = stdout
}

In Executor we are simply executing the command blocks.

Usage

Just use make to get the executable minishell program.

If you encounter a readline problem when compiling with make first use make readline then use make. This should solve the problem.

After compiling it run it like ./minishell.