match

Allows through only the lines whose token matches a regular expression.

Usage

match pattern [position]

• pattern — a regular expression to search for.

• position — which space-separated token to check (default: 0).

Example

Find words containing a doubled vowel:

$ cat words.txt | match "aa|ee|ii|oo|uu"

Regular expressions often contain characters with special meaning to the shell (like |), so it’s safest to wrap the pattern in quotation marks.