Bash Debugging

With "set -x"

In bash scripts, the -x flag turns on trace functionality. It can be turned on with "set -x" or with the -x option in the bash invocation like "bash -x" and even works in the shebang.

#!/usr/bin/env bash -x

This next code snippit can be safely placed in your .bash_profile without any side effects (assuming vendor scripts don't contain debug code). It sets a prompt that you only see when the -x option is set in bash. It adds script line numbers and function names to the -x trace output.

# for xtrace (set -x)
export PS4='+(${BASH_SOURCE}:${LINENO}): ${FUNCNAME[0]:+${FUNCNAME[0]}(): }'