A shell script is a program that can be executed in Unix shell. Sometimes a shell script does not work as intended. To debug and find the problem in shell script we can use the options provided by shell to debug the script.
In bash shell there are x and v options that can be used while running a script.
% bash –xv
With option v all the input lines are printed by shell. With option x all the simple commands are printed in expanded format. We can see all the arguments passed to a command with –x option.Read the full book at www.amazon.com