Question $2$

Write a C program $($name it shell.c$)$ to develop a basic Unix shell interface to execute basic Unix

commands input by the user. This program will use parent$-$child process to run the commands that are

entered by the user. The parent process will print the shell prompt "myshell$>"$ where the user will input

the Unix commands. The parent process will parse the input and identify the command along with

arguments and child will execute using execvp$()$ function. You can call following functions to

implement the program:

while $(1)$ loop creates an infinite loop for the shell to continuously accept commands.

fgets $()$ is used to read a command from the standard input.

strtok $()$ is used to split the command into arguments $($for use with execvp $()).$

fork $()$ creates a new process, and execvp $()$ replaces the child process with a new program.

wait $()$ is used in the parent process to wait for the completion of the child process.

After the command is executed $($or not$),$ the main menu is reproduced again, unless the command

is $\text{'}q\text{'}$ in which case the program terminates $($use strcmp $()$ to compare the command with $\text{'}q\text{'}$

to exit the program$).$

If the user press enter without entering command, then programme should show "myshell$>"$

prompt again and be ready to accept new command. The other implementation details are at your

discretion, and you are free to explore.

Use the following command to compile the code:

$ gcc $-$Werror $-$Wall $-$g $-$std$=$gnu$99$ shell.c $-$o shell

The above code will create the $./$shell executable file

The expected output for executing:

When running on Linux Terminal the command $./$shell$.$ It will print the prompt and you can enter any

Unix command:

myshell$>$ echo hello

hello

myshell$>$ uname

Linux

myshell$>$ touch file.txt

myshell$>$q