Shell

Introduction

This is a simple shell program written in C that replicates most of the functionalities of the popular shells like bash and zsh.

Instructions

• To run, compile using make and run ./gosh.
• The shell starts with the current directory (from which ./gosh is run) as the HOME directory.

Extension of Assignment-2

Signal Handling

• Ctrl-c kills the current foreground process using the SIGINT signal.
• Ctrl-z send the current foreground process to background using the SIGTSTP signal.
• Ctrl-d logs out of the shell and goes back to the shell from where ./gosh is run. Tried implementing using SIGQUIT signal but not working properly.

I/O Redirection

• Handled >, >> and < operators in the input by opening (in the child process) the corresponding input/output file, and using dup2() function to redirect all the contents from STDOUT/STDIN to the file opened.

Background Jobs

• A dynamically allocated array is maintained to store the info of the background processes.
• jobs command prints the background jobs with their pid and other info. Options: -r prints only the running processes, -s prints only the stopped processes.
• sig command takes two arguments process number and signal number. It send the corresponding signal to the process with process number.