I'm having some problems with some scripts in bash about errors and unexpected behavior I'd like to look for the causes of the problems so i can apply solutions Is there any way to turn a debug mode for bash to get more information?

Best Answer

Start your bash script with bash -x ./script.sh or add in your script set -x to see debug output.

Additional with bash 4.1 or later.

If you want to write the output of debug in a separate file add this into your script

exec 5> debug_output.txt
BASH_XTRACEFD="5"

See: https://stackoverflow.com/a/25593226/3776858

Add this if you want to see line numbers

PS4='$LINENO: '

If you have access to logger command then you can use this to write debug output via your syslog with timestamp, script name and line number:

#!/bin/bash

exec 5> >(logger -t $0)
BASH_XTRACEFD="5"
PS4='$LINENO: '
set -x

# Place your code here

You can use option -p of logger command to set an individual facility and level to write output via local syslog to its own logfile.