Question: The one-liner should:

* solve a real-world problem
* not be extensively cryptic (should be easy to understand and reproduce)
* be worth the time it takes to write it (should not be too clever)

I'm looking for practical tips and tricks (complementary examples for `perldoc perlrun`).

Answer: 
Squid log files. They're great, aren't they? Except by default they have seconds-from-the-epoch as the time field. Here's a one-liner that reads from a squid log file and converts the time into a human readable date:

```
perl -pe's/([\d.]+)/localtime $1/e;' access.log

```

With a small tweak, you can make it only display lines with a keyword you're interested in. The following watches for stackoverflow.com accesses and prints only those lines, with a human readable date. To make it more useful, I'm giving it the output of `tail -f`, so I can see accesses in real time:

```
tail -f access.log | perl -ne's/([\d.]+)/localtime $1/e,print if /stackoverflow\.com/'

```
At some time I found that anything I would want to do with Perl that is short enough to be done on the command line with 'perl -e' can be done better, easier and faster with normal Z shell features without the hassle of quoting. E.g. the example above could be done like this:

```
srt=(*.srt); for foo in *.avi; mv $srt[1] ${foo:r}.srt && srt=($srt[2,-1])

```