The Linux Command Line

Chapter 30. Troubleshooting

As our scripts become more complex, it’s time to take a look at what happens when things go wrong and they don’t do what we want. In this chapter, we’ll look at some of the common kinds of errors that occur in scripts and describe a few techniques that can be used to track down and eradicate problems.

Syntactic Errors

One general class of errors is syntactic. Syntactic errors involve mistyping some element of shell syntax. In most cases, these kinds of errors will lead to the shell refusing to execute the script.

In the following discussions, we will use this script to demonstrate common types of errors:

#!/bin/bash # trouble: script to demonstrate common errors number=1 if [ $number = 1 ]; then echo "Number is equal to ...