A basic shell program which reads the user input from stdin, parses the input to interpret IO redirections and pipes and execute them. After executing a command, it again waits for user input until the user enters the exit command. It is able to handle nested commands.
Example : ls -l | wc > out.txt
Below is the list of features implemented :
| Syntax | Meaning |
|---|---|
| command | execute the command and wait for the command to finish, print error message if the command is invalid |
| command > filename | redirect stdout to file “filename”. If the file does not exist create one, otherwise, overwrite the existing file |
| command >> filename | If the filename already exists append the stdout output, otherwise, create a new file |
| 1>filename | redirect stdout to filename |
| 2>filename | redirect stderr to filename |
| 2>&1 | redirect stderr to stdout |
| command < filename | use file descriptor 0 (stdin) for filename. If command tries to read from stdin, effectively it will read from filename |
| exit | exit from the shell program |
On ctrl+c (SIGINT), the program should kill the currently executing process (if any), and start waiting for an input command.
Contributers : Atul Anand, Dashmesh Singh, Kanupriya Singh