Forced Variable Interpolation In Here Document

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

I'm working on a script that needs to send a series of commands to another command line program. So I open a pipe to the other utility and then create a here document so other non-perl programmers can understand and change the commands if need be. For one of the commands, I want to force the string to be equivlent:

my $label = $_ . "Obsolete" . $timestamp;
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This works when I concat the strings before the here document. Is there a way to do this inside the here document section? I've tried:

Command -v$_Obsolete$timestamp
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But the $_ and Obsolete don't appear because Perl is looking for a scalar named _Obsolete. Thanks!

davorg: changed title to "Interpolation"

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Re: Forced Variable Intropolation In Here Document by Masem (Monsignor) on Nov 27, 2001 at 22:59 UTC
Use `${varname}` to isolate (or force) interpolation. In your case, `${_}Obsolete` does the trick. ----------------------------------------------------- Dr. Michael K. Neylon - mneylon-pm@masemware.com \|\| "You've left the lens cap of your mind on again, Pinky" - The Brain "I can see my house from here!" It's not what you know, but knowing how to find it if you don't know that's important	[reply] [d/l] [select]
Re: Forced Variable Intropolation In Here Document by dws (Chancellor) on Nov 27, 2001 at 23:01 UTC
But the $_ and Obsolete don't appear because Perl is looking for a scalar named _Obsolete. perlman:perldata to the rescue. The workaround you need is the section titled "Scalar value constructors". It looks like: `Command -v${_}Obsolete$timestamp`	[reply] [d/l]
(tye)Re: Forced Variable Intropolation In Here Document by tye (Sage) on Nov 27, 2001 at 23:33 UTC
Oh sure, giving the standard `${_}` answer is easy. But it is more fun to use `Command -v$_$,Obsolete$timestamp` (and sometimes more readable). (: - tye (but my friends call me "Tye")	[reply] [d/l] [select]
Re: Forced Variable Intropolation In Here Document by Dogma (Pilgrim) on Nov 28, 2001 at 00:12 UTC
comment removed	[reply] [d/l]
Re: Re: Forced Variable Intropolation In Here Document by qslack (Scribe) on Nov 28, 2001 at 05:33 UTC
Except that the original poster wanted it equivalent to: `$_ . "Obsolete" . $timestamp` He doesn't have a variable by the name of $Obsolete. But otherwise, you're correct. Quinn Slack perl -e 's ssfhjok qupyrqs&&tr sfjkohpyuqrspitnrapj"hs&&eval&&s&&&'	[reply] [d/l]