grep is the name of a common utility on many Unix or unix like systems.
Folklore says that the name represents a command that developers in the old days used to issue within their editor or other similar program:
g/re/p
which was a global {regular expression} print command.
Grep reads through one or more input streams (stdin or files), searching for a string of text which represents some for of a regular expression, and, depending on options provided, may produce the matching lines of input.
RS wrote this tiny, and feature-poor, emulation for use on PocketPC (but it should run elsewhere too):
proc grep {re args} {
set files [eval glob -types f $args]
foreach file $files {
set fp [open $file]
while {[gets $fp line] >= 0} {
if [regexp -- $re $line] {
if {[llength $files] > 1} {puts -nonewline $file:}
puts $line
}
}
close $fp
}
}
see also a grep-like utility - A little file searcher with GUI