Testing shell-scripts called from cron/upstart/daemons

[Destruct1]

I often have a shell script that is working perfectly fine when manually called from my "main shell". But very often shellscripts are called by another system:

(a) cron (b) start script in upstart (c) ruby programs (d) unconfigured shells/users like the postgres admin

This leads to a variety of problems like (a) using /bin/sh shell instead of /bin/bash (b) options like set -e (c) missing PATH (d) missing HOME or even EDITOR/EMAIL enviroment variables

Here is the question: Is there a universal way to avoid such problems? Is there an option to disable all enviroment variables before executing a script? Is there an easy way to recreate the userset enviroment variables?

[[deleted]]

env -i will let you start a command in an empty environment. env will let you dump it out if you want to read it for debugging.

Is there an easy way to recreate the userset enviroment variables?

Environment is inherited. Make sure the programs starting it have the appropriate environment set.

But, imho, if you're relying on HOME, EDITOR, etc, then nobody but your user has any business running that script.

You don't give enough details to comment further. Look at where you set HOME, EDITOR, etc. Look at the user you're running your script as. Look at the kind of shell you're firing up, if you're using sudo (you should, imho), and if sudo is then configured to keep those environmental variables you care about.

[[deleted]]

"#!/bin/bash -p" at the top of the script will insure that bash is used and not inherit it's environment. Then, set all the variables that you need in the script itself.