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: 
Please see my slides for ["A Field Guide To The Perl Command Line Options."](https://web.archive.org/web/20120916013412/http://petdance.com/perl/command-line-options.pdf)
Network administrators have the tendency to misconfigure "subnet address" as "host address" especially while using Cisco ASDM auto-suggest. This straightforward one-liner scans the configuration files for any such configuration errors.

incorrect usage: `permit host 10.1.1.0` 

correct usage: `permit 10.1.1.0 255.255.255.0`

```
perl -ne "print if /host ([\w\-\.]+){3}\.0 /" *.conf

```

This was tested and used on Windows, please suggest if it should be modified in any way for correct usage.