#!/usr/bin/perl use strict; my %hTmp; while () { if (/^{(\w*)}/) { $hTmp{$1}++; } } for my $key (keys %hTmp) { if ($hTmp{$key} > 1) { print "The key $key is multiple\n"; } else { print "$key\n"; } } __DATA__ ^C^D^V^V^A os01 0002 010101 R S 0012310002 00003466^B{IT} R {SOURCETAG} 0012310002 {ACCESSION} 000000 {PUBLICATION} THE ORLANDO SENTINEL {EDITION} METRO {DATE} 010101 {DATE} 010102 {TDATE} Monday, January 1, 2001 {SECTION} SPECIAL SECTION {PAGE} E2 {ZONE} FLORIDA {KEYWORDS} VOLUNTEER SUPPORT {SECTION} SPECIAL SECTION1 {SEND} YES ^C^D^V^V^A os01 0003 010101 R S 0012310003 00001558^B{IT} R {SOURCETAG} 0012310003 {ACCESSION} 000000 {PUBLICATION} THE ORLANDO SENTINEL {HI}hi {EDITION} METRO {DATE} 010101 {TDATE} Monday, January 1, 2001 {SEND} YES