topic Command Substitution is not working in Operating System - HP-UX

Command Substitution is not working

vinodan — Wed, 04 Jan 2006 01:49:23 GMT

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

Re: Command Substitution is not working

Muthukumar_5 — Wed, 04 Jan 2006 02:05:21 GMT

Can you try like this,

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

It has to work.

-Muthu

Re: Command Substitution is not working

vinodan — Wed, 04 Jan 2006 02:19:47 GMT

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

Re: Command Substitution is not working

Muthukumar_5 — Wed, 04 Jan 2006 03:07:59 GMT

Try this:

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

--
Muthu

Re: Command Substitution is not working

Oviwan — Wed, 04 Jan 2006 03:24:21 GMT

Hi

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

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

Regards

Re: Command Substitution is not working

Andrew Merritt_2 — Wed, 04 Jan 2006 07:58:05 GMT

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

Re: Command Substitution is not working

TwoProc — Wed, 04 Jan 2006 10:21:20 GMT

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.