Re: problem with string literal in system()

You seem to be confused about how interpolation works. In your first example, $cmd is interpolated in the double quotes, and $cmd happens to contain a string that contains some things that look like variables. If you wanted those variables to then be interpolated, you'd need to eval that code somehow. This however would not be considered exactly safe. But to directly answer the question something to the effect of:

$cmd = eval "\"$cmd\"";

will give you the string that you want to use in your system command.

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Re^2: problem with string literal in system() by ikegami (Patriarch) on Sep 22, 2006 at 02:11 UTC
With the given contents of `$cmd`, that expression won't compile, so `$cmd` will be `undef`. If you want templating functionality, use a templating system! Using `eval EXPR` is such a bad idea.	[reply] [d/l] [select]
Re^3: problem with string literal in system() by cephas (Pilgrim) on Sep 22, 2006 at 03:23 UTC
Its not trying to execute `$cmd`. Its wrapping `$cmd`with `"`'s, and then eval'ing. It will return a string with the values interpolated. Update: ikegami is correct, the way the command is layed out, it will generate an error. I thought ikegami was trying to point out that the command itself wasn't valid perl, not that it was building an invalid string (that is bad perl). The point of the story is that interpolation doesn't run arbitrarily deep, if you want another layer, you'll have to eval, and get all of the problems that go along with it.	[reply] [d/l] [select]
Re^4: problem with string literal in system() by ikegami (Patriarch) on Sep 22, 2006 at 05:09 UTC
You forgot to take into account that `$cmd` contains double quotes. Why didn't you try it? `use strict; use warnings; my $cmd = '/opt/sudo/sudo /usr/bin/su - $ENV{LOGNAME} -c "$someScript" +'; $cmd = eval "\"$cmd\""; print($cmd, "\n");` [download] outputs `Scalar found where operator expected at (eval 1) line 1, near ""/opt/s +udo/sudo /usr/bin/su - $ENV{LOGNAME} -c "$someScript" (Missing operator before $someScript?) String found where operator expected at (eval 1) line 1, near "$someSc +ript""" (Missing operator before ""?) Use of uninitialized value in print at 574310.pl line 5.` [download]	[reply] [d/l] [select]
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Re^4: problem with string literal in system() by cvg2mco (Novice) on Sep 22, 2006 at 22:06 UTC
Thanks for the suggestions cephas and ikegami. I did the below: `my $testCmd = (split /\\|/, $configLine)[1]; my $cmd = eval "qq($testCmd)"; my $activity = "testActivity"; system("$cmd 1>$activity.stdout 2>$activity.stderr");` [download] I noticed that it was giving an UnInitialized variable message when I tried to `print "$cmd\n";` And, it executed the command. Thanks again	[reply] [d/l] [select]