http://www.perlmonks.org?node_id=1137298


in reply to Re^2: remove lines that do not match search pattern
in thread remove lines that do not match search pattern

OT

Filtering with Tcl/expect: 

#!/usr/bin/expect

while {[gets stdin line] >= 0} {
  if {[regexp {([[:xdigit:]]{2}:?){6}} $line]} {
    puts $line
  }
}

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