CodeBlab

I was recently asked to hunt a bug in some of my old code. It was a shell script generating Postscript, generating .PNG files for a website. It had “organically” grown over some years and started generating bad Postscript starting May 1^st. Since Postscript is well designed and has good error handling, it did not take long to find the problem. The word May had not been replaced by a 120 (the year day number of May 1^st). Here is a sniped:

Note the ‘r’ that should be a ‘y’ in the center LOC. My bad. However, I realized that, in theory, this error could have been caught (by sed) because the second /[Mm]ar[^ ]*/ would not ever be satisfied. Sadly, I can’t make sed find my bad code, but I can dream, can’t I?