Some specific remarks on your shell script at the end... > If I "set -o pipefail", won't any failure in this chain of pipes halt the program? No, due to your

Some specific remarks on your shell script at the end... > If I "set -o pipefail", won't any failure in this chain of pipes halt the program? No, due to your use of the || operator: foo | bar || baz ...as a whole will always exit 0, even if foo or baz exits non-zero. The precedence there is actually ( foo | bar ) || baz I.e, the pipe operator binds tighter than any of the logic operators. Also, `set -o pipefail` doesn't cause your shell script to exit on the first error; you need `set -e` or explicit exit status checking for that. What `set -o pipefail` actually does is change the way exit status for a pipeline as a whole works. Consider the following pipeline: foo | bar | baz Without `set -o pipefail`, if either foo or bar exit non-zero, but baz exits zero, this pipeline will appear to have succeeded, because by default a pipeline gets the exit status of its last element. Ignoring errors is bad. So `set -o pipefail` makes the pipeline take the exit status of the last element that failed (if any failed). Regarding `set -u`, I don't personally use it, I just check that kind of stuff at the beginning of the script. Now, on to your shell script example: in practice you'll never see an error because both grep and sed return true even when no matching or substitution is done. You also have a useless use of cat [1] at the beginning; just use grep directly on that file. I would suggest simply doing sed -ne 's/^HomeCommunityId=//p' "${EXTERNAL_VARIABLE}"/adapter.properties for grabbing that variable. Then see if the variable is empty with a `-z` test. Hope this helps. Shell is weird but definitely worth learning! [1] http://en.wikipedia.org/wiki/Cat_(Unix)#Useless_use_of_cat http://en.wikipedia.org/wiki/Cat_(Unix)#Useless_use_of_cat