3 Common Ways to Debug a Bash Script

Debug Your Bash Scripts Like A Pro.

Bash scripts, because of their nature and intended usage, are tricky to debug and test. In this short article let’s look at 3 common methods that developers use to debug bash shell scripts.

The following are the 3 commonly used methods:

1. echo command

2. Enabling debugging mode

3. trap command

The Good Old Echo

The echo command is the console.log() equivalent in the bash land. It is quite simple and can come in handy while debugging a script.

By using echo statements throughout your script, you can output the value of variables, the result of commands, and any other information that is useful in understanding how your script is working. For example, consider the following script:

#!/bin/bash
echo "Starting script"
VAR1="Hello"
VAR2="World"
echo "VAR1 is: $VAR1"
echo "VAR2 is: $VAR2"
echo "Concatenating variables..."
result="$VAR1 $VAR2"
echo "Result is: $result"
echo "Exiting script"

In this script, we use echo statements to output the value of variables VAR1 and VAR2, as well as the result of concatenating these variables. This output can be helpful in understanding how the script is working.

Although the scripts you’d encounter on production won’t be this simple, you get the idea of how this could be used.

The Debugging Mode

Another useful tool for debugging is the set command. When you run the set -x command in your script, it will enable debugging mode.