avoid pipefail issue with create_passwd

[simonLeary42]

if you want to use bash "strict mode" in a batch connect job, you might be confused when your job fails.

#!/bin/bash
set -euo pipefail
set -x
password="$(generate_passwd)
echo "hello, world!"

output.log:

++ tr -cd '[:alnum:]'
++ head -c16
+ password=IhZj0VloAJ4r0FwN

create_passwd successfully creates a password, but since head closes its stdin while tr is still trying to write into it, tr gets a SIGPIPE and proces a return code = 128 + SIGPIPE = 141. set -o pipefail means that the first nonzero exit code of any process in the pipeline is used for the whole pipeline, and set -e means that execution stops after the 1st nonzero exit code.

To prevent this, make sure that pipefail is disabled for create_passwd. To avoid changing the option in the original shell, check_passwd runs in a subshell (() instead of {}). subshell behavior tested:

$ set -o pipefail; set -o | grep pipefail; (set +o pipefail; set -o | grep pipefail); set -o | grep pipefail
pipefail       	on
pipefail       	off
pipefail       	on

[johrstrom]

OK I'll have to test this a bit because I'm not really a bash/shell expert.