Question - How do I get my Perl program to display an error message and exit?

Answer - use the die function - for example
     die "Unable to open input file";

Question - That's great, but how do I prevent it telling me the line number it failed at in my code?

Answer - add a \n to the end of the string you pass to die - for example
     die "Unable to open input file\n";

Question - What if I'm writing a Perl module that another programmer will be using?   Can I tell him the line number in his code that the failure occurs at?

Answer - use croak instead of die.  You'll need to call in the standarp Perl carp module.  For example
     use carp;
     ..........
     croak "Unable to open input file";

Edit - it's probably a good idea to tell the user as much useful information as you can in an error message.  My example should really have given the name of the file that wasn't available. Just saying "cannot open file" is unhelpful and prone to lead to lots of support calls

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