Command Substitution is not working

[vinodan]

When I am calling a command from a perl script via command ticks i.e ` then if my command has a | it fails
eg.
=`ls | wc -l` doesn't give me any output in the variable
but =`ls` works

The same works on other servers. Perl instalation, version, modules etc is all the same. | works on command prompt but not via programs

$ uname -a
HP-UX Server_Name B.11.11 U 9000/800 1849201262 unlimited-user license

$ perl -v

This is perl, v5.8.7 built for PA-RISC2.0-thread-multi

[Muthukumar_5]

Can you try like this,

perl -e '$var=`ls | wc -l`;print $var;'

It has to work.

-Muthu

[vinodan]

Hi,
It doesn't work

testsw /home/testsw>perl -e '$var=`ls | wc -l`;print $var;'
testsw /home/testsw>

but

testsw /home/testsw>perl -e '$var=`ls`;print $var;'
a.pl
data
ftpdtls.txt
ftpuploaddtls.txt
getPatchInfo
getclientdetails.pl
maintainhash
maintainhashcron.sh
nohup.out
setdistenv
testing.sh
testsw /home/testsw>


So i'm back to where I was, the | doesn't work from perl

[Muthukumar_5]

Try this:

# perl -We '$var=`ls | wc -l`;print $var;'
# perl -We '$var=qx[ls | wc -l];print $var;'

--
Muthu

[Oviwan]

Hi

what is with the other pipe-operators (<,>,|)?
does this works?

#perl -e '`ls > list`;'
#cat list

Regards

[Andrew Merritt_2]

So this is a problem on only one system, is that right?

Perhaps it's not a problem with perl, but with the environment you're running it in. What shell are you running on the system that doesn't work, and what on the systems that do?

What is the output of 'stty -a' on the non-working and working systems?

What happens if you put the line in a file, and run that (e.g. put the line in a file and run the file with 'sh /tmp/filename' or even 'sh -x /tmp/filename')?

Andrew

[TwoProc]

As I was reading this, I began to suspect where Andrew went with it, that is, maybe you've got the "|" redefined in your stty settings.

run "stty -a" and see if you see a "|" symbol in there.