C-Shell

A linux shell written in C to implement all inbuilt shell commands and some additional user-defined commands. It has functionalities to run both background and foreground processes.Piping , redirection and signal handling are also implemented. Error handling is done wherever necessary.

COMMANDS

1. echo [arguments] Print arguments on the shell.

2. pwd Shows the current working directory path.

3. pinfo <pid> Prints details of the process with given pid.If no argument is provided it takes pid of current process by default. Details include : PID, Process Status, Memory , Executable Path.

4. cd Changes the directory

cd [argument] Changes the current directory to the directory mentioned in argument.

Cd ..Takes back to the previous directory.

cd or cd ~ Take to the home direcotry.

cd / Takes to root directory.

5. ls Lists all contents of current directory.

ls -a Lists all hidden files also.

ls -l Long Listing of all files.

ls -al Long Listing of all files including hidden files.

6. setenv [var] [val] Sets value of the environment variable 'var' to value 'val'.

unsetenv [var] Unsets the value of environment variable 'var'.

7. jobs Prints all the jobs in order of their creation along with their Unique Id,current status, Name of the job, Pid.

8.fg [job_id] Brings the Job with given job_id to the foregound process i.e brings stopped or sleeping process to foreground.

bg[job_id] Takes the job with given job_id to the background process.

9. Ctrl-ZChanges status of currently running job to stop and takes it to the background.

Ctrl-C Interrupts the running process.

10. Overkill Kills all jobs at once.

kjob [job_id] [Signal_number] Sends signal 'signal_number' to process with given job_id.

11. cronjob -c <command name> -t <time_interval> -p <total period of running> eg. cronjob -c ls -t 3 -p 6 This command should execute ls command after every 3 seconds until 6 seconds are elapsed.

12. quit Exits the shell.

13. Handles multiple piping and redirection properly.