Searching string in a multiline file using perl - perl

Question

I'm trying to find a match in a multi-line string using this script.
It works only when there's one row in the destination file.
I would like to know if there's any substitution for $_ in order to search a multi-line text?
#!/usr/bin/perl
my $time=`date +%D_%H:%M`;
chomp($time);
my $last_location=`cat /file.txt`;
chomp($last_location);
open (ERRORLOG, ">>/errors.log") || die "failed to open errorlog file \n$!\n\a";
open (MESSAGES, "</logfile") || die "failed to open alarms file \n$!\n\a";
seek(MESSAGES, 0, 2) || die "Couldn't seek to pos: 0 at end of file $!\n";
$end_position = tell(MESSAGES);
if ($end_position < $last_location) {
$last_location=0;
}
if ($end_position > $last_location) {
seek(MESSAGES, $last_location, 0) || die "Couldn't seek to pos: $last_location $! \n";
$num_of_messages_sent=0;
while (<MESSAGES>) {
chomp;
$line_to_check $_;
if ($line_to_check =~ /some text/ ) {
print ERRORLOG "$time: $line_to_check \n";
if ($num_of_messages_sent < 4) {
do something;
}
if ($num_of_messages_sent == 4) {
do something;
}
#increase counter
$num_of_messages_sent = $num_of_messages_sent + 1;
}
}
$last_location = tell(MESSAGES);
# print "last: $last_location , end: $end_position \n";
`echo $last_location >/file_last_location.txt`;
}
close (ERRORLOG);
close (MESSAGES);

Answer 1

Looks better this way:
while (my $line = <MESSAGES>) {
chomp($line);
print "line : $line\n";
if ($line =~ m!your_regexp_here!i){
print ERRORLOG "$time: $line_to_check \n";
$num_of_messages_sent++;
print "\tMATCH\tline: $line\n";
if ($num_of_messages_sent < 4){
print "Found $num_of_messages_sent matches\n";
}
}
}