pipex

Description:

Recreate the behavior of the shell pipe operator, connecting the output of one command to the input of another.

Requirements:

Your program should be executed as follows: ./pipex file1 cmd1 cmd2 file2

It must take 4 arguments:

• file1 and file2 are file names.
• cmd1 and cmd2 are shell commands with their parameters.

It must behave exactly like the following shell command: $> < file1 cmd1 | cmd2 > file2.

Examples: $> ./pipex infile "ls -l" "wc -l" outfile

Its behavior should be equivalent to: < infile ls -l | wc -l > outfile

$> ./pipex infile "grep a1" "wc -w" outfile.

Its behavior should be equivalent to: < infile grep a1 | wc -w > outfile

Bonus part:

The bonus files (see src dir) handles multiple pipes, and supports « and » when the first parameter is "here_doc". The bonus program works well but I did it only as a transition exercise for the follow-up project, Minishell. So for a much more complete, and better resolved project see the Minishell repo.

Learning process:

Key things learned from this project:

• Unix processes.
• Forking processes and executing commands with execve.
• Using pipes to communicate between processes.
• Environment variables. Most importantly PATH, that the system searches for paths of commands to be executed.
• Shell behavior.

Useful sources:

• These video tutorials about Unix processes in C.
• The GNU bash manual's section on redirections.