Backtics and variables

rpike has asked for the wisdom of the Perl Monks concerning the following question:

When using backtics to execute a command will variables be substituted correctly if placed within? For example,

   $result = 'somecommand $filename';
[download]

Will the variable filename have it value substituted in or will it get interpreted literally as $filename? If it doesn't is there something in Activestate's verion of Perl to allow me to accomplish this? Thanks.

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Re: Backtics and variables by Corion (Patriarch) on Mar 16, 2010 at 13:43 UTC
Single quotes don't interpolate. Double quotes and backticks do. See perlop. If you're curious about what a string contains, consider printing it.	[reply]
Re: Backtics and variables by toolic (Bishop) on Mar 16, 2010 at 14:22 UTC
When using backtics to execute a command will variables be substituted correctly if placed within? Yes, backticks (qx) will interpolate variable values. As Corion said, refer to perlop. `$result = 'somecommand $filename';` [download] Will the variable filename have it value substituted in or will it get interpreted literally as $filename? You used single quotes (q) in your example, not backticks. So, your question does not seem to match your example code. Since single quotes do not interpolate, `$result` will contain the literal string `$filename`, which you can easily prove to yourself by using print to inspect its value, as Corion also pointed out. You probably want: $result = `somecommand $filename`; [download] or: `$result = qx(somecommand $filename);` [download]	[reply] [d/l] [select]
Re: Backtics and variables by jacaril (Beadle) on Mar 16, 2010 at 14:02 UTC
Value will be subbed in with all Perl versions I have used. my $filename = "foo"; `echo $filename > $filename`; [download] Creates file foo with 1 line foo in the file.	[reply] [d/l]