/Drama_Shell

An simple & interactive user defined bash-like shell in " C " (which also supports semi-colon separated list of commands).

Primary LanguageC

An interactive user defined bash-like C-Shell

Coded by: Akash Verma

This README file contains :

  1. Information About the Shell
  2. How to run
  3. List of builtin commands
  4. Features
  5. File structure

About The Shell

An interactive user defined bash-like shell which supports semi-colon separated list of commands.It can take commands in input check if a builtin exists if exists then run the builtin else run it as separate process. The shell also supports input and output redirection along with piping of commands.

Running the program

  • make
  • ./drama

To quit the shell

  • quit OR exit

Builts in Commands

Command Description Flags No. of Arguments
ls Shows files and directory -a,-l,-al,-la 0 or more
pwd Shows current directory - -
cd Change directory ~ 1 or more
echo Print on terminal - 0 or more
exit Exit terminal - -
pinfo Display process Info of given process id - 0 or 1
setenv Can be used to set(i.e create or change) environment variable - 1 or 2
unsetenv Can be used to unset(remove) an environment variable - 1
jobs Shows all background process with status and index - -
kjob Used to send kill signal to process listed in jobs - 2
fg Used to bring a background process to foreground - 1
bg Used to make stopped background process running - 1
overkill Kills all the background processes - -
quit Graceful exits - -
mkdir Creates a new directory -p 1 or 2

Features

  • Supports semi-colon separated commands
  • Modular code structure
  • Supports input and output file redirection
  • Supports background process creation when command followed by '&'.
  • Prints exit message when background exits
  • Supports piping of commands
  • Handles Ctrl + C and Ctrl + Z signals
  • Unique builtins like pinfo,jobs, kjob, overkill ,quit.

File Structure

  • drama_run : infinite loop for the shell to run.
  • drama_readandsplit : consists of the read() function used by run and tokenizes the input.
  • drama_check : checks wether process is background or not.
  • drama_builtin : Implements built in commands cd, echo, pwd, calls ls function and history.
  • drama_ls : This implements ls command along with the flags -a, -l, &, -al, -la.
  • drama_pinfo : Implements pinfo command.
  • drama_notbuiltin : Implements regular shell functions using exec.
  • drama_displayprompt : Displays the prompt.
  • drama_piping : do piping.
  • drama_redirection : do redirection.
  • drama_argumentize : count the args passed.

Akash Verma