Re^3: system command

I want to find the total number of lines without opening the file

There's simply no way to do that.

If you use wc -l, it opens the file, reads through the content (counting newlines), closes the file and returns a count. Whether you do the reading in Perl, or some external program does, it still must occur.

Also, i am keen to learn how can we use the output of system command (that is directed to STDOUT) within our program

Use backticks:

  my $file = '/path/to/file';
  my $output = `/bin/wc -l '$file'`;
[download]

Note $file is subject to shell-escaping rules.

Alternatively, you can use the pipe form of open as ikegami has already observed.

-David

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Re^4: system command by ikegami (Patriarch) on Oct 31, 2007 at 03:39 UTC
Note $file is subject to shell-escaping rules Easily handled: my $file = '/path/to/file'; my $output = `/bin/wc -l \Q$file\E`; [download]	[reply] [d/l]