As Perl allows for complicated data structures by virtue of references to hashes and arrays, it’s often useful to look into what’s going on there. In my case, it was on the output of a large JSON parse. So to make a long story short, if $tree is a reference to the data structure, go [...]
Leave no leftover childred One of the really tricky things about a Perl script that forks this way or another, is how to make sure that the children vanish after the parent has exited. This is an issue both if the children were created with a fork() call, or with a safe pipe, as with [...]
TL;DR: SELECT queries in Perl for numerical columns suddenly turned to zeros after a software upgrade. This is a really peculiar problem I had after my web hosting provider upgraded some database related software on the server: Numbers that were read with SELECT queries from the database were suddenly all zeros. Spoiler: It’s about running [...]
To make a long story short: $ perl -pi.bak -e ‘s/this/that/g’ `find inhere/ -type f` or to delete entire lines that contain a certain substring: $ perl -pi.bak -e ‘s/^.*?RUNTIME_PARAM.(?:OUTPUT|SHARED)DIR.*?[\n\r]+//gm’ $(find . -iname \*.xci) This will create backup files. Yes, you want them. Really. Otherwise, in particular under Windows, errors like this may show up: [...]
The mission What I really needed was a proper timeout for a certain chunk of Perl code. There is alarm() of course, but one has to watch out with certain commands that cancel it (sleep() and other less expected functions). The script also uses “system()” to run processes outside the native Perl domain, so getting [...]
Just set up your mail server? Congratulations! Now you should test it. In particular, check if it relays mails to other servers and if the response time is reasonable. Here’s a script for doing the testing. Just edit the arguments to send_mail() to match your setting. #!/usr/bin/perl use warnings; use strict; use Net::SMTP; send_mail(’127.0.0.1′, # [...]
Suppose that some hodge-podge of scripts and template files create a single file, which has multiple encoding of Hebrew. That is, both UTF-8 and windos-1255. If the different encodings don’t appear in the same lines, the following script makes it all UTF-8: #!/usr/bin/perl use strict; use warnings; use Encode; binmode(STDOUT, “:utf8″); while (defined (my $l [...]
Git has this thing about trailing white spaces in source files, for good reasons. Somehow it looks like there isn’t a widely spread utility for cleaning up a lot of files in one go. On the other hand, there are plenty of them out there, but none met my needs. So I wrote yet another [...]
It may look like a stupid idea, since the CRC32 has been implemented in some Perl modules which can be downloaded from CPAN. But all functions I found involve an XS part, which essentially means that a compilation of C code has to take place during the installation. In other words, these modules can’t be [...]
OK, so the board designer just sent me an updated schematics of the design. Are there any changes? Comparing the schematics itself is hopeless. So I’ll compare the PCAD netfiles (those with a .NET extension). I mean, they are simple text files, after all. The problem is that Orcad feels free to change the order [...]
