Scripting Best Practices

Treat Your Variables Right

Scripting languages are incredibly useful for quick-fix scripts. The problem with this is when the quick-fix script is still in place 6 months down the line, at which point the corners you cut because, hey, it's just a short-term fix, come back to bite you. Read on for some best practice tips to make the experience less painful.

(A note: my own scripting languages of choice are perl and bash, but the principles hold across other languages.)

Treat your variables right

When you pass variables into a script or a subroutine, don't just use the default names. Give them real names immediately - it's much easier to keep track of what you're passing in and what you're doing with it. A perl example:

sub concatenate_files {
	my ($firstfile, $secondfile) = @_;
	// rest of the subroutine
}

And while we're naming variables: name them something sensible. Something that'll be meaningful when you read this, say, tomorrow morning before coffee. So, $filelist, not $fl.

Don't hard-code anything. Put all your static values into variables, and collect them all at the top of your script.

#!/bin/bash
EMAIL=admin@example.com
LOGFILE=/var/log/locallogs/mailscript.log

That way when something changes (your email, the mailserver address) and the script breaks, the fix will be a straightforward two-second job.