String manipulation https://www.thegeekstuff.com/2010/07/bash-string-manipulation/
Bash 101 Hacks https://www.thegeekstuff.com/bash-101-hacks-ebook/
Error handling in bash #https://stackoverflow.com/questions/64786/error-handling-in-bash
IBM i Pase/Qshell https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_73/rzahz/rzahzpdf.pdf
https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_74/rzahz/rzahzpdf.pdf
File checks https://linuxize.com/post/bash-check-if-file-exists/
Bash scripting tutorial https://www.tutorialkart.com/bash-shell-scripting