Shell Programming and Scripting

#! /usr/bin/perl -s -wnl

BEGIN {
$pattern or   
  warn"Usage: $0 -pattern='RE' [FILE1 ....]\n" and
exit 255;
}

/$pattern/ and print;

#! /usr/bin/perl -s -wnl

BEGIN {
$pattern or   
  warn"Usage: $0 -pattern='RE' [FILE1 ....]\n" and
exit 255;
}

($last_match) = /($pattern)/;
print defined $last_match ? $last_match : 'no match was found';

#! /usr/bin/perl -s -wnl
/aaa|bbb/ and print;

#! /usr/bin/perl -s -wnl
/(aaa|bbb)/ and $last{$1}=$_;
END { print $last{"aaa"}; print $last{"bbb"} }

while(<>){
if(index($_,"aaa")>=0)
{
$a=$_;
}
if(index($_,"bbb")>=0)
{
$b=$_;
}
}
print $a;
print $b;