Use "-x" to enable debug output of executed lines. It can be run on an entire session or script, or enabled programmatically within a script.
Run a script with debug output enabled:
$ bash -x myscript.sh
Or
$ bash --debug myscript.sh
Turn on debugging within a bash script. It may optionally be turned back on, though debug output is automatically reset when the script exits.
#!/bin/bash
set -x # Enable debugging
# some code here
set +x # Disable debugging output.