A practice I've found valuable in the past is the script command. SCRIPT(1) script - make typescript of terminal session Manually run through a process over

A practice I've found valuable in the past is the script command. SCRIPT(1) script - make typescript of terminal session Manually run through a process over and over, checking the intermediate outcomes until its right and tight. Then take the last iteration from script and make that into a shell script. After testing an tweaking few more times now make that portable in a system language of your choice. A kludge I frequently used was just copy it to a Perl file as back-quoted script lines, then replace each with a proper statement, same thing works with python calling process/system/exec things that return proper exit values. Dirty, mechanical, industrial programming. No elegance in sight. But it works reliably in most cases and leaves an understandable trail for debug.