{
  local $/ = undef;
  open(FILE,$filename) or die "open failed on $filename: $!";
  $wholetext = <FILE>;
  close FILE;
}
if ( $wholetext =~ /\b$searchword\b/ ) {
     # do something
}

##</code><code>##

open( FILE, $filename ) or die "yadda yadda";
@data = <FILE>;
if ( grep /\b$searchword\b/, @data ) {
    # do something;
}