This is a text-only version of the following page on https://raymii.org: --- Title : Bash Bits: Debug Logging Author : Remy van Elst Date : 15-09-2013 URL : https://raymii.org/s/snippets/Bash_Bits_Debug_Logging.html Format : Markdown/HTML --- Bash Bits are small examples and tips for Bash Scripts. This bash bit shows you how to add debug logging to a bash script.

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[All Bash Bits can be found using this link][2] Debug logging can be very usefull when scripts or programs don't do what you want. I use it in most of my scripts. First we create a simple one line function named `debug`: function debug() { ((DEBUG_LOG)) && echo "### $*"; } As you can see, very simple. If the variable `DEBUG_LOG` is set, then it prints all the text given to the function. If the variable is not set, it does nothing. Now if we want to debug log something, we place the following line in our script: debug "This is debug output". When we want to see the debug logging, before we run the script, we set the variable `DEBUG_LOG` to 1: export DEBUG_LOG=1 # or just for this script run: DEBUG_LOG=1 ./script.sh Example with debug logging: [10:52:51] [remy@gateway] [ ~/conf (master) ] $ export DEBUG_LOG=1 [10:52:56] [remy@gateway] [ ~/conf (master) ] $ ./setup.sh ### vimrc done ### screenrc done ### bash done Example without debug logging: [10:53:11] [remy@gateway] [ ~/conf (master) ] $ unset DEBUG_LOG [10:53:11] [remy@gateway] [ ~/conf (master) ] $ ./setup.sh [1]: https://www.digitalocean.com/?refcode=7435ae6b8212 [2]: https://raymii.org/s/tags/bash-bits.html --- License: All the text on this website is free as in freedom unless stated otherwise. This means you can use it in any way you want, you can copy it, change it the way you like and republish it, as long as you release the (modified) content under the same license to give others the same freedoms you've got and place my name and a link to this site with the article as source. This site uses Google Analytics for statistics and Google Adwords for advertisements. You are tracked and Google knows everything about you. Use an adblocker like ublock-origin if you don't want it. All the code on this website is licensed under the GNU GPL v3 license unless already licensed under a license which does not allows this form of licensing or if another license is stated on that page / in that software: This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . Just to be clear, the information on this website is for meant for educational purposes and you use it at your own risk. I do not take responsibility if you screw something up. Use common sense, do not 'rm -rf /' as root for example. If you have any questions then do not hesitate to contact me. See https://raymii.org/s/static/About.html for details.