$line = "wc -l test.txt"; how to execute

[polka4ever]

Hello, I would like to run a count of rows on a flat file. From a unix prompt, i would just type wc -l, right? but I want to do this within a perl script.

So - how do i get this to execute? I am a brand new perl user. I tried this:

$line = "wc -l test.txt";
print "$line\n";

But that literally prints out the $line.

Pls help!

 

[PaulTEG]

$line = `wc -l test.txt`;
print "$line\n";

using backticks (`) not single quotes (')

There are other methods, such as opening the file in perl, slurping it into an array, and printing the numebr of items in the array

HTH
--Paul


Spend an hour a week on CPAN, helps cure all known programming ailments ;-)

 

[polka4ever]

wow, thank you for the advice. I will try tomorrow ... I did open the file in perl - so I will also look into slurping.

I really appreciate this, and thank you for the help!

Best,

P4E

 

[KevinADC]

another way:

my $n = 0;
open(FH,'file.txt');
$n++ while (<FH>);
close(FH);
print $n.

but of you are going to read the file into an array anyway, you can do it that way and kill two birds with one stone. If not, I would use the above instead.

 

[rharsh]

Also, the $. variable contains the current line number for the last filehandle accessed. So this would work as well:

open FH, "< a.txt";
map {;} <FH>; 
#my @lines = <FH>  # if you want to store the data
print $., "\n";

See perldoc perlvar if you want more info on predifined variables.