42_pipex

The purpose of this project is to discover in detail pipe UNIX mechanism by writing my own "piping" program in C.

Assignment

• The program is able to handle multiple pipes.
  • This: ./pipex file1 cmd1 cmd2 cmd3 ... cmdn file2 will behave like < file1 cmd1 | cmd2 | cmd3 ... | cmdn > file2
• The program supports << and >> when first parameter is 'here_doc'.
  • This: ./pipex here_doc LIMITER cmd cmd1 file will behave like cmd << LIMITER | cmd1 >> file

Examples

• ./pipex infile "ls -l" "wc -l" outfile will behave like < infile ls -l | wc -l > outfile
• ./pipex infile "grep a1" "wc -w" outfile will behave like < infile grep a1 | wc -w > outfile
• ./pipex here_doc EOF cat "wc -l" outfile will behave like cat << EOF | wc -l >> outfile

How to use the program

1. git clone git@github.com:m-bartos/42_pipex.git
2. make
3. Play with the program. If you run just ./pipex, program will show you how the right format of input should look like.

You have to create file1 before executing the program!

What I learned during this project

• I learned more about pipes in Unix terminal
• I learned about how multiprocessing and pipes in C work
• I learned about redirections of STD_IN and STD_OUT
• I applied various new functions, including pipe, fork, dup2, execve, perror, exit, etc.
• I had to handle several mallocs and ensured accurate freeing of allocated memory

Thanks and kudos

Acknowledgements to CodeVault's YouTube playlist on Unix Processes in C for the valuable insights.