Running the program

Type in the example program using a text editor, and save it. Emacs is a good editor to use for this because it has its own Perl mode which formats lines nicely when you hit tab (use `M-x perl-mode'). But as ever, use whichever you're most comfortable with.

After you've entered and saved the program make sure the file is executable by using the command

chmod u+x progname

at the UNIX prompt, where progname is the filename of the program. Now to run the program just type any of the following at the prompt .perl progname

./progname
progname




If something goes wrong then you may get error messages, or you may get nothing. You can always run the program with warnings using the command:

perl -w progname


At the prompt. This will display warnings and other (hopefully) helpful messages before it tries to execute the program. To run the program with a debugger use the command perl -d progname
When the file is executed Perl first compiles it and then executes that compiled version. So after a short pause for compilation the program should run quite quickly. This also explains why you can get compilation errors when you execute a Perl file which consists only of text.
Make sure your program works before proceeding. The program's output may be slightly unexpected - at least it isn't very pretty. We'll look next at variables and then tie this in with prettier printing.

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