for (<FILEHANDLE>);
print "FILEHANDLE contains $. lines";
[download]

See perldoc perlvar for more info

Editor's Note:
$. is reset on an explicit close. Opening an open filehandle first does an implicit close on it, then opens it. This does NOT reset $. to zero. This is one of the many reasons to explicitly close filehandles when you are done with them. <> Uses the default filehandle and does not explicitly close it, which is why you get the behaviour that nuance mentioned. Of course, you can also set $. yourself as a point to start counting from (although this does NOT tell the read operator to start at the specified line, $. is just a counter) and you can scope $. with local $. as well.

wc -l file
[download]

From Perl you can read the file into an array, then use the array in scalar context to get the number of lines. Or, you could loop through and count, something like:

my $cnt;
open(FH,"file") or die "Damn. $!";
$cnt++ while <FH>;
close FH;
[download]

Or, use $. (perldoc perlvar)

while (<FH>) {}
print $.;
[download]

Or, to skip blank lines...

open(FH,"calendar.cgi") or die "Damn. $!";
while (<FH>) { $cnt++ if  !/^\s+?$/;}
close FH;
[download]

Cheers,
KM

How do I count the number of lines in a file?

One fairly efficient way is to count newlines in the file. The following program uses a feature of tr///, as documented in perlop. If your text file doesn't end with a newline, then it's not really a proper text file, so this may report one fewer line than you expect.

           $lines = 0;
           open(FILE, $filename) or die "Can't open `$filename': $!";
           while (sysread FILE, $buffer, 4096) {
               $lines += ($buffer =~ tr/\n//);
           }
           close FILE;
[download]

This assumes no funny games with newline translations.

while(<>){};
print "$. lines\n";
[download]

my $total = @{[<FILE>]};
print $total,"\n";
[download]

open(FILE, "filename");
  @lines = <FILE>;
close(FILE);

$num = @lines;
[download]

--newbie00

@lines could get rather large depending on the size of the file; how about

open(FILE, "filename") or die "couldn't open filename: $!"; # check re
+turn status of system calls!
for ($count = 0; <FILE>; $count++) {}
[download]

Josh

That's a duplicate answer. See the original about half-way down the list of all answers for this question.

-- Ken

Originally posted as a Categorized Answer.

  $line_count = `wc -l < $file`;
[download]