Here are some common techniques to debug a bash script:

1. Use the -x option: By adding #!/bin/bash -x at the top of your script, it will print each line of the script before executing it, making it easier to see what’s going wrong.
2. Use the echo command: You can use the echo command to print the values of variables and expressions, helping you understand the flow of your script and identify the source of any errors.
3. Use the set -e option: This option causes the script to exit immediately if a command returns a non-zero exit status. This makes it easier to identify errors, as you will know exactly which command caused the problem.
4. Use the trap command: The trap command allows you to specify a command to run when the script receives a signal. This can be useful for debugging, as you can use it to print a message or the values of variables when an error occurs.
5. Use the bash -n option: This option causes bash to check the syntax of the script without executing it. This can be useful for catching syntax errors before you run the script.

These are just a few of the many tools and techniques available for debugging bash scripts. Experiment with different approaches and find the ones that work best for you.