Here is a very quick and easy perl one-liner that I use fairly often. When I am working with data that is contextualized in chunks of paragraphs (such as Cassandra columnfamily info), I often want to quickly find a single paragraph for a specific piece of information. Here is how I go about doing that in perl:
my_output_command | perl -00 -ne 'm/ninja/ && print'
This results in any paragraph containing the word “ninja” to be printed. The way this works is by the magic of the -00 flag. This flag causes the perl line-separator variable($/) to be set to ‘\n\n’, resulting in the one-liner iterating over STDIN for each paragraph, instead of each line.