User's manual. Section 1.

RUNFOR(1): run commands for input lines matching expressions



Runfor takes pairs of expressions and commands as arguments and reads input lines. For each input line it runs the command with the first matching expression. Expressions are written like in sre(2). The command strings given may contain back-references of the form \0, \1, ... that are replaced with the matched string or substring.

If further input lines matching the expression for a given command are received while the command is running, they are discarded.



User's manual. Section 1.