Problem
1. Write a script that looks in the entire file system to locate a filename supplied as argument. If the file is found, the script should display its absolute pathname and last modification time without saving any data in files.
2. If the command set `cat foo` generates the error unknown option, what could be the reason, assuming that foo is a small readable file?
3. If a script uses 12 arguments, how will you access the last one?
4. Devise a script that looks at every component of PATH and checks whether the directory exists and is also accessible.