C-Shell

Introduction

This is an implementation of a Linux shell written in C language with support for piping, I/O redirection, background and foreground processes, history retrieval, custom commands, etc.

Run the shell

Run "make all" to create shell, run "./shell" to execute

Functionality and Limitations

• Built-in commands: ls [al], echo, pwd, cd, quit, history, pinfo, nightswatch, setenv, unsetenv, jobs, kjobs, overkill, fg, bg, cronjob, quit
• Process management including foreground and background processes and switching between them.
• Piping and redirection
• Signal handling for signals like SIGINT and SIGTSTP
• A prompt that shows the username, hostname and the current working directory
• Command history and up arrow command recall across sessions
• Appropriate error handling

File Breakdown

• cd.c - cd command
• echo.c - echo command
• execInput.c - external commands
• globals.c - contains functions that are used across various files
• history.c - history command, also contains function to write to history after each command is executed
• input.c - parse input
• ls.c - ls command
• nightswatch.c - nightswatch command
• pinfo.c - pinfo command
• pwd.c - pwd command
• shell.c - main file, responsible for printing prompt, taking input, and calling respective functions