use strict ; use warnings ;

my $data ;
{ local $/ ; $data = <DATA> ; } ;

my $s = 'bc' ;  # Substring to search for in left hand side

my @r = ($data =~ m/$s[^\s]*[ \t]+(.*)/g) ;
print "@r\n" ;

__DATA__
abcd	s1
efgh	s2
ijklm	s3
nopq	s4
bc	s5
aqbc	s6
rst	s7
uvwx	s8
yz	s9

##</code><code>##

my $data = "\n" ;
{ local $/ ; $data .= <DATA> ; } ;

my $s = 'bc' ;  # Substring to search for in left hand side

my @r = ($data =~ m/\n.*?$s[^\s]*[ \t]+(.*)/g) ;