Over the next three nights, Erwin didn’t rewrite the code. He performed surgery with the PDF as his scalpel. He wrapped bare blocks in do { } . He replaced if(!$var) with unless($var) . He added perlcritic to the CI pipeline and watched its severity ratings drop from “brutal” to “stern.”
Erwin was a archaeologist of broken things. While other sysadmins chased cloud-native glitter, Erwin maintained the legacy core—a sprawling Perl backend that processed global financial settlements. The code was old enough to vote, buy a drink, and run for local office. It had no tests, no consistent indentation, and variables named things like $x2a and $foo_final_FINAL . perl best practices pdf
He felt a pang of shame. The core script had neither. Over the next three nights, Erwin didn’t rewrite the code
Chapter 4: Don’t use $a and $b outside of sort() . He replaced if(
The system didn’t break again. And when someone asked why, Erwin would tap the side of his monitor and say: “The PDF teaches you how to write code for the person who finds your body.”
He thought of the thirty-seven lines where $a held a transaction ID and $b held a customer’s social security number.
By Thursday, the Perl script was still ugly. But it was consistent in its ugliness. Every else was cuddled. Every subroutine had a return . Every filehandle used the three-argument open . The auditors, who didn’t read Perl, saw a printed metric: “Cyclomatic complexity: reduced 42%.” They signed off.
