Hamaarour / minishell

This project is about creating a simple shell - essentially, my own little bash. Through this project, I've learned a lot about processes and file descriptors.

This project is about creating a simple shell

MiniShell will introduce you to the world of shells, which provide a convenient text interface to interact with your system. Shells might seem very easy to understand but have very specific and defined behaviour in almost every single case, most of which will need to be handled properly

The Challenge

This was probably the biggest project I've done so far, as well as the first one I did as a group. The goal was to create a mini version of bash, I say mini but it was still a huge project. We had to learn how bash takes arguments, parses them, and executes them. We had to incorporate the following features:

• Display a promt while waiting for a new commmand.
• Have a working history.
• Find and launch executables (using the PATH variable or an absolute path).
• Handle ' (single) and " (double) quotes like in bash.
• Implement redirections such as:
  • < redirect input.
  • > redirect output.
  • << heredoc (doesn't affect history).
  • >> redirect output in append mode.
• Implement | (pipes).
• Handle environment variables.
• Handle $?.
• ctrl-C, ctrl-D, and ctrl-\ should behave like in bash.
• Recreate the following builtins:
  • echo with option -n.
  • cd with only a relative or absolute path.
  • pwd (no flags).
  • export (no flags).
  • unset (no flags).
  • env (no flags or arguments).
  • exit (no flags).

Installation

Clone the repository:

git clone https://github.com/Hamaarour/minishell.git
cd minishell
make

Run Minishell

./minishell

Some commands to try:

As this project is made to mimic bash, you can try any commands you normally would try in bash.

If you really can't think of anything try some of the following. You do have to enter each line separately as the program doesn't handle new lines.

ls -la | grep a | tr 'a-z' 'A-Z'

cat << EOF > file
cat file
rm file

ls | rev > file
cat file
rev file | cat
rm file

to exit the program:

exit
We didn't have to implement && and ||, or wildcards, as well as any special symbols that weren't specifically asked for.  We were also told that when in doubt, take bash as a reference.  This sometimes led to discussions on wether or not we had to implement something, the result of which was usually