#!/usr/bin/tcl

#

# Replace string with another string -OR- include

# only lines successfully modified with a regular

# expression.

#

fconfigure stdout -translation binary -encoding binary

fconfigure stderr -translation binary -encoding binary

set mode [string tolower [lindex $argv 0]]

set from [lindex $argv 1]

set to [lindex $argv 2]

if {$mode ni [list exact regsub include]} {exit 1}

if {[string length $from]==0} {exit 2}

while {![eof stdin]} {

set line [gets stdin]

if {[eof stdin]} break

switch -exact $mode {

exact {set line [string map [list $from $to] $line]}

regsub {regsub -all -- $from $line $to line}

include {if {[regsub -all -- $from $line $to line]==0} continue}

}

puts stdout $line

}