Linux_C_Shell : My Shell

Welcome to my Linux C-Shell. Hope you like it :)

Introduction

This is the implementation of the basic version of the Linux Shell. It is completely written in C language. It supports most of the basic linux commands including semicolon separated commands. Extra tabs and spaces are taken care of. Error handling is done in all appropriate cases.

How to run the shell

Fork the repository on to your local machine and run the following commands -

make main
./a.out

Features

The commands supported are as follows -

• pwd - prints the current working directory

  • Code : pwd.c

• echo - prints the message on the terminal

  echo <text>
  

  • Code : echo.c

• cd - changes the directory based on the flags given -

  cd
  cd .
  cd ..
  cd ~
  cd -
  cd <directory>
  

  • Error Handling : Displays an error if the directory is not present
  • Code : cd.c

• ls - lists the contents of a particular directory based on the flags given -

  ls
  ls -a
  ls -l
  ls -al
  ls -la
  ls <directory>
  

  • Error Handling : Displays an error if the directory is not present
  • Code : ls.c

• pinfo - prints the details of the process whose pid is specified. If not mentioned, prints the details for the current process

  pinfo
  pinfo <pid>
  

  • Error Handiling : Displays an error if pid is not present
  • Code : pinfo.c

• setenv - sets the environment variable to a specified value (creates a new environment variable if not already present). If no value is specified then it sets the variable to an empty value

  setenv [var] <value>
  

  • Error Handling : Displays an error in case of too few or too much arguments
  • Code : setenvv() in envs.c

• unsetenv - unsets the environment variable

  unsetenv [var] 
  

  • Error Handling : Displays an error in case of too few or too much arguments
  • Code : unsetenvv() in envs.c

• Other commands : implementing some other commands using execvp

  command <space>
  command <file>
  

  • Error Handling : Displays an error if the command doesn't exist
  • Code : others.c

To Quit the shell

Run the following command -

quit

Other Files

• header.h and takeinput.h - for header files and declarations
• main.c - the main file with init_shell() function displays message upon initialisation and quit_shell() function displays message upon exiting the shell
• takeinput.c - the input file
• prompt.c - for displaying prompt