Catch command used to execute a script and handle if any error happen. Catch command will return 0 on success and 1 on error. Catch command will give error message to a variable.
For examples we will execute expr command to raise divide by zero error to examine what a catch command will do.
Here we can see on error catch will return 1 and error message variable will be filled.
We can also use catch to simply ignore error on executed script !