in reply to different terminal

if you re running in a Linux environment and want a script to collect the results of running a command (or commands) why bother with a terminal at all? Something like this should work (weak example): 

#!/usr/bin/perl -w 
use strict;
my $cmd=qq@
date 
who
ps -ef
netstat -i 
ifconfig -a 
) | 
@;

open CMD, $cmd or die $cmd . ":$!";

my @lines=<CMD>;  # slurp! 

close CMD;
chomp @lines;

# do something here.

[download]

Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg

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Re^2: different terminal
by GotToBTru (Prior) on Jun 10, 2014 at 17:12 UTC

    I'm curious what the ) | does.

    1 Peter 4:10
[reply]
[d/l]

      | opens a pipe (see perldoc perlopentut). ( ... ) delimits a subshell, and can be tested at the command line:

      davido@somehost:~$ (
> date
> who
> )
Tue Jun 10 11:20:34 MDT 2014
davido   :0           2014-06-09 19:35 (:0)
davido   pts/0        2014-06-09 19:38 (:0)

      [download]

      See This stackexchange explanation.


      Dave

[reply]
[d/l]
[select]
      It works better without the ")".

      With it, the shell complains: 

      sh: 6: Syntax error: ")" unexpected

      [download]
      but the output is produced anyway.

              What is the sound of Perl? Is it not the sound of a wall that people have stopped banging their heads against?
                    -Larry Wall, 1992

[reply]
[d/l]

        Actual demo code: 

        sh-4.1# cat demo.pl
#!/usr/bin/perl -w

use strict;

my $cmd=qq@
(
date
netstat -i
who
cat /etc/debian_version
)
@;

open PIPE,"$cmd |" or die "$cmd:$!";

my @lines=<PIPE>;

printf "%s\n",join("\n",@lines);

        [download]
        produces 
        sh-4.1# perl demo.pl
Tue Jun 10 13:46:05 EDT 2014

Kernel Interface table

Iface   MTU Met   RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX
+-OVR Flg

eth0       1500 0  19404144      0      0 0      23405161      0      
+0      0 BMRU

lo        65536 0   2016133      0      0 0       2016133      0      
+0      0 LRU

root     pts/0        2014-06-10 13:11 (144.160.226.53)

6.0.9

        [download]

        NOTE: there should be a chomp in there somewhere, but I forgot...

        Peter L. Berghold -- Unix Professional
        Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg
[reply]
[d/l]
[select]

        Funny, doesn't do that on my Linux (Debian 7) box... 

        sh-4.1# (
> ls
> pwd
> date
> )


deb7-postinstall-pmaster.sh  deb7-postinstall.sh  list.txt
/var/www/scripts
Tue Jun 10 13:40:37 EDT 2014
sh-4.1#

        [download]

        Peter L. Berghold -- Unix Professional
        Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg
[reply]
[d/l]

In Section Seekers of Perl Wisdom