I get an error "^M: command not found" or "$'\r': command not found" after submitting a script

Described problem is caused by the fact that your batch script was written in non-Unix operational system (Windows) which uses different characters to mark end of a line. To get rid of the faulty endlines, use dos2unix command:

(BUSTER)user123@skirit:~$ dos2unix myscriph.sh

To test for the type of endlines, use command file:

(BUSTER)user123@skirit:~$ file myscriph.sh
myscript.sh: UTF-8 Unicode text, with CRLF line terminators

If the file report CRLF line terminators, your script needs to be converted to run on Linux.