in reply to how to store values from system command

In your sample, $val will contain the return code from ls. Most system commands return 0 or undef on success, so your system("ls -lrt "); call is succeeding (I'm quite sure ls can fail; I just can't remember seeing it do so.).

As ikegami and andyford mentioned, using system is almost certainly not the best solution. For one thing, it uses a sub-shell, where using glob or opendir doesn't.

You could try something like this (see stat):

#!perl use strict; use warnings; my @list = glob("*"); foreach(@list){ (my $dev, my $ino, my $mode, my $nlink, my $uid, my $gid, my $rdev, my $size, my $atime, my $mtime, my $ctime, my $blksize, my $blocks) = stat; # do processing here }

yeah, verily, an update

ikegami pointed out that system only uses a subshell if the command contains shell metacharacters. In any case, unless you need the data exactly as produced by ls, using the Perl functions is certainly more portable (Windows doesn't have ls), and possibly faster.


emc

At that time [1909] the chief engineer was almost always the chief test pilot as well. That had the fortunate result of eliminating poor engineering early in aviation.


—Igor Sikorsky, reported in AOPA Pilot magazine February 2003.

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Re^2: how to store values from system command
by ikegami (Patriarch) on Nov 21, 2006 at 20:07 UTC

    $val will contain the return code from ls.

    [system] uses a sub-shell

    One of those statments is necessarily false. If a shell is used, $val will contain the return value of the shell, not ls.

    So does system use a shell? It depends. "If there is only one scalar argument, the argument is checked for shell metacharacters, and if there are any, the entire argument is passed to the system's command shell for parsing." Otherwise, no.

    In this case? no. However, I still wouldn't use ls.

    Some examples:

    system('command foobar') # no shell system('command "foo bar"') # shell system('command', 'foo bar') # no shell system('sort < file | uniq') # shell