Shell. c below is a stripped down shell program. It will run a Unix command without any arguments. Copyand save the program as shell. c. Modify the program so that it can execute any shell command. It shouldbe able to take at least 2 arguments. Usually, you need to parse the command line you enter. Using execvpinstead of execlp will probably help. It should work on any UNIX command consisting of 0-2 argumentsafter the command entered by the user, and be error free. The following are a few test cases that the usercould enter.$ cp file1 file2$ ls -l$ whochar *strtok(char *str, const char *delim)is a useful function for parsing the input string. Youcan see below how it used "\n" as a delimiter to get everything before that character. You can specify " " asa delimiter to split the string into arguments. The first time you use it, give it a string as the first parameterto tokenize. This will return the first token. You can then use it subsequent times with NULL as the firstparameter and it will return subsequent tokens in order. After the last token was returned, it returns NULL. For example if you wrote:charinput [ ] = " Hello World ! " ;strtok ( input , " " ) ;strtok (NULL, " " ) ;strtok (NULL, " " ) ;...the first call would return "Hello". The second call would return "World!". And the third call wouldreturn NULL.