a. Write the command line that will find the files that start with the word 'sys' and end with '21' in our active directory. (ex: sys_log.s21) b. In the same command line, add a command that will delete found files after asking us before each operation and receiving a positive response. c. This command line generates also some error messages along with the find results. Add the grep command, to the command line you typed in item (a) , that would suppress the "permission denied" error (STDERR). d. Interpret the following command line (Guidance: first explain each component and then the result to be obtained). $ find / -ls -print