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Full Discussion: Trouble executing piped shell commands in perl code
Top Forums Shell Programming and Scripting Trouble executing piped shell commands in perl code Post 302629047 by sam05121988 on Tuesday 24th of April 2012 09:03:24 AM
Old 04-24-2012
Lightbulb Trouble executing piped shell commands in perl code
I am trying to execute a piped combination of shell commands inside a perl program.
However, it is not working as desired.

This is my program, i am trying to print only filenames from the output of ls -l

Code:
$ cat list_test
#!/usr/bin/perl -w
use strict;
my $count=0;
my @list=`ls -l|awk '{print $9}'`;
print "@list";

it produces output as

Code:
$ ./list_test
Use of uninitialized value in concatenation (.) or string at ./list_test line 5.
total 104
 -rwxr-xr-x 1 sam ugroup  59 Mar 28 08:13 ch2_p1
 -rwxr-xr-x 1 sam ugroup 127 Mar 28 08:18 ch2_p2
 -rwxr-xr-x 1 sam ugroup 202 Mar 28 08:21 ch2_p3
 -rwxr-xr-x 1 sam ugroup 175 Mar 28 08:28 ch2_p4
 -rwxr-xr-x 1 sam ugroup 170 Mar 28 09:52 ch2_p5
 -rwxr-xr-x 1 sam ugroup  86 Apr 10 09:20 ch3_p1
 -rwxr-xr-x 1 sam ugroup 193 Apr 10 09:34 ch3_p2
 -rwxr-xr-x 1 sam ugroup 232 Apr 10 10:16 ch3_p3
 -rwxr-xr-x 1 sam ugroup 334 Apr 17 03:16 ch4_p1
 -rwxr-xr-x 1 sam ugroup 142 Apr 17 03:20 ch4_p2
 -rwxr-xr-x 1 sam ugroup 418 Apr 17 03:34 ch4_p3
 -rwxr-xr-x 1 sam ugroup  38 Apr 18 02:29 ch5_p1
 -rwxr-xr-x 1 sam ugroup 180 Apr 18 02:49 ch5_p2
 -rwxr-xr-x 1 sam ugroup 259 Apr 18 02:53 ch5_p3
 -rwxr-xr-x 1 sam ugroup 308 Apr 20 00:46 ch6_p1
 -rwxr-xr-x 1 sam ugroup 261 Apr 20 00:56 ch6_p2
 -rwxr-xr-x 1 sam ugroup 220 Apr 20 01:17 ch6_p3
 -rwxr-xr-x 1 sam ugroup  77 Apr 20 03:35 ch7_p1
 -rwxr-xr-x 1 sam ugroup  81 Apr 20 03:36 ch7_p2
 -rwxr-xr-x 1 sam ugroup  75 Apr 20 03:36 ch7_p3
 -rwxr-xr-x 1 sam ugroup  84 Apr 20 04:42 ch7_p4
 -rwxr-xr-x 1 sam ugroup  82 Apr 20 04:42 ch7_p5
 -rwxr-xr-x 1 sam ugroup  92 Apr 20 04:45 ch7_p6
 -rw-rw-rw- 1 sam ugroup 218 Apr 20 04:46 ch7_sample1
 -rwxr-xr-x 1 sam ugroup  82 Apr 23 05:33 list.pl
 -rwxr-xr-x 1 sam ugroup 155 Apr 24 08:52 list_test

however, when i execute those commands on command line it executes perfectly(this is how the output should be of the perl code)

Code:
$ ls -l | awk '{print $9}'
ch2_p1
ch2_p2
ch2_p3
ch2_p4
ch2_p5
ch3_p1
ch3_p2
ch3_p3
ch4_p1
ch4_p2
ch4_p3
ch5_p1
ch5_p2
ch5_p3
ch6_p1
ch6_p2
ch6_p3
ch7_p1
ch7_p2
ch7_p3
ch7_p4
ch7_p5
ch7_p6
ch7_sample1
list.pl
list_test

please help!
 

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LEARN ABOUT OSX

platform::shell

platform::shell(n)					       Tcl Bundled Packages						platform::shell(n)

__________________________________________________________________________________________________________________________________________________

NAME

       platform::shell - System identification support code and utilities

SYNOPSIS

       package require platform::shell ?1.1.4?

       platform::shell::generic shell
       platform::shell::identify shell
       platform::shell::platform shell
_________________________________________________________________

DESCRIPTION

       The platform::shell package provides several utility commands useful for the identification of the architecture of a specific Tcl shell.

       This  package  allows the identification of the architecture of a specific Tcl shell different from the shell running the package. The only
       requirement is that the other shell (identified by its path), is actually executable on the current machine.

       While for most platform this means that the architecture of the interrogated shell is identical to the architecture of  the  running  shell
       this  is  not generally true. A counter example are all platforms which have 32 and 64 bit variants and where a 64bit system is able to run
       32bit code. For these running and interrogated shell may have different 32/64 bit settings and thus different identifiers.

       For applications like a code repository it is important to identify the architecture of the shell which will  actually  run  the  installed
       packages, versus the architecture of the shell running the repository software.

COMMANDS

       platform::shell::identify shell
	      This command does the same identification as platform::identify, for the specified Tcl shell, in contrast to the running shell.

       platform::shell::generic shell
	      This command does the same identification as platform::generic, for the specified Tcl shell, in contrast to the running shell.

       platform::shell::platform shell
	      This command returns the contents of tcl_platform(platform) for the specified Tcl shell.

KEYWORDS

       operating system, cpu architecture, platform, architecture

platform::shell 						       1.1.4							platform::shell(n)
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