Lets talk backticks

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

How does perl manage backticks do they pass through the shell? or is it ... deeper than that ?

The question is really quite simple, how does this not work:

perl -e'print `for i in {1,2,3}; do echo $i; done;`'
[download]

But this does:

perl -e'print `ls | head -n 1`'
[download]

Evan Carroll
www.EvanCarroll.com

Comment on Lets talk backticks Select or Download Code

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Re: Lets talk backticks by davidrw (Prior) on May 31, 2006 at 01:48 UTC
This works: perl -e'print `for i in {1,2,3}; do echo \$i; done;`' [download] You have to escape the $ so it makes it to the shell .. quoting perlop (The 'I/O Operators' section): A string enclosed by backticks (grave accents) first undergoes double-quote interpolation.	[reply] [d/l]
Re: Lets talk backticks by Fletch (Bishop) on May 31, 2006 at 12:43 UTC
Checking perlop the very first sentence under the `qx//` operator is: qx/STRING/ `STRING` A string which is (possibly) interpolated and then executed as a system command with "/bin/sh" or its equivalent. What part of executed as a system command with "/bin/sh" or its equivalent was unclear?	[reply] [d/l]