I'd probably use word boundaries. This not only address the 19 problem, but also pme's concerns about 90. It would presume your summaries do not contain numbers surrounded by punctuation or whitespace.

Also, as you are taking an arbitrary string as input, you might want to use quotemeta to escape special characters.

if($line =~ /\b\Q$TEMP\E\b/) {
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Other nice additions might include three-argument open, indirect file handles, and the strict pragma.

!/usr/bin/perl
use strict;
use warnings;

my $conf_file = 'something';

open(my $in,'<', $conf_file) or die("unable to open $conf_file");
my @lines = <$in>;
print @lines;

print "Please choose a number from the list above: ";
chomp(my $input = <STDIN>);
#    $input=trim($input);
print "Your Choice was: $input \n";

for my $line (@lines) {
    if ($line =~ /\b\Q$input:\E\b/) {
        print " exact match: $& \n" ;
        print " after match: $' \n" ;
        my $svc = $';
        print "ServiceL $svc \n";
    }
}
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