Linux Shell in C

This Linux Shell in C can be run by compiling with make and then running with ./ainux. 'history' has been implemented on top of the basic requirements.

How to Run the Shell

1. Compile the project using the Makefile:

   make

2. Run the shell executable:

   ./ainux

Files

makefile

• Used to compile all the files present.

main.c

• Main file where we call all our functions to execute commands.
• Tokenizes inputs and separates commands by semicolons.

prompt.c

• Prints the prompt of the shell and changes the prompt accordingly if we change the present directory.

cd.c

• Allows us to change the directory that we are present in.
• Takes both absolute and relative paths.

pwd.c

• Displays the directory we are present in.
• Displays relative paths if the directory is inside the shell directory and absolute paths otherwise.

echo.c

• Prints the argument given.

ls.c

• Allows us to display the files present in the current directory.
• Accepts relative and absolute paths.
• Accepts flags to print hidden files and file permissions.
• Works for multiple directories in any order of arguments.

fore.c

• Allows us to implement foreground processes.

back.c

• Allows us to implement background processes and prints whenever the background process finishes executing.

pinfo.c

• Prints process-related info.
• Prints info of the currently running process if no PID is given or gives the info of any specified PID.
• Accepts at most 1 PID and gives an error otherwise.

history.c

• Keeps commands entered into the shell in hist.txt.

historyprint.c

• Prints the history of commands run in the shell.
• The user can specify the number of commands to show up to 20.
• Just running history without specifying the number of commands prints the last 10 commands entered.
• Specifying a number higher than 20 just prints 20 commands.

hist.txt

• Stores history of commands up to 20 commands.

bg.c

• Changes the state of a stopped background job with a given job number to running.

fg.c

• Brings a job with a given job number to the foreground and changes its state to running if it isn't already.

env.c

• Implements setenv and unsetenv commands.

jobs.c

• Prints all running background processes with associated information pertaining to each.

kjob.c

• Sends a given signal to the job of a given job number.

overkill.c

• Kills all the background processes.

redirection.c

• Implements input/output redirection.

sig.c

• Implements signal handling.

Error Handling

Corresponding error messages will be displayed in case invalid arguments or an incorrect number of arguments are provided upon the execution of a certain command, depending on their functionality in the terminal.

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Enjoy using the shell!