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Perl script running multiple commands at once

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# 1  
Old 04-02-2015
Perl script running multiple commands at once
Hi All,
I have put a perl script together to go and collect some information from multiple nodes/endpoints. The script works absolutly fine however I want to make it quicker.

You will see in the below that my script calls an expect script called ssh_run_cmd2.exp followed by the IP of the node in question. Once that has finished it moves on to the next node.

Is there a way of getting it to call all the commands such as the below
Code:
ssh_run_cmd2.exp xxx.xxx.xxx.xxx $log "show association peer-address $ip

to trigger at once rather than waiting for each one to finsih.

None of the commands are dependant on the previous one.

Code:
        for (`./ssh_run_cmd2.exp xxx.xxx.xxx.xxx $log "show association peer-address $ip"`) {
                if (/^\s+ID       : (\S+)/) {
                        $ID = $1;
                        $peerfound = 'YES';
                } elsif (/(No matching peer)\S+/) {
                        $peerfoundoutcome = "$1"
                } elsif (/\S{7}(\S+)\s/) {
                        $hostname = $1;
                        }
                }
        for (`./ssh_run_cmd2.exp xxx.xxx.xxx.xxx $log "show association peer-address $ip"`) {
                if (/^\s+ID       : (\S+)/) {
                        $ID1 = $1;
                        $peerfound1 = 'YES';
                } elsif (/(No matching peer)\S+/) {
                        $peerfoundoutcome1 = "$1"
                } elsif (/\S{7}(\S+)\s/) {
                        $hostname1 = $1;
                        }
                }

Thanks in advance
# 2  
Old 04-02-2015
Hi,

i dont know it is that what you want, but easy way to do it is:
you can try run everything in background with outputs to files (for exmpl first line> file all other lines >> file last line >> end) and then create loop to collect info from created files and if you want loop till all files got end
# 3  
Old 04-02-2015
Hi bacarrdy, Thanks for responding. Im not sure i understand your comment. would you mind explain how exactly I would do what your mentioned ?
# 4  
Old 04-02-2015
you can run each command ./ssh_run_cmd2.exp $xxx.xxx.xxx.xxx $log > $xxx.xxx.xxx.xxx & in background and then read outputs from $xxx.xxx.xxx.xxx files

so then all your commands (./ssh_run_cmd2.exp) will run in one time and they start to create some files and for thous files you can run another loop to read them
# 5  
Old 04-02-2015
not sure if i can do that as there multiple arguements defined on command line which require to remain in place.

basically i need this to run
./ssh_run_cmd2.exp xxx.xxx.xxx.xxx $log "show association peer-address $ip

along with this (this IP's will be different)
./ssh_run_cmd2.exp xxx.xxx.xxx.xxx $log "show association peer-address $ip

but they need to run simultaniously rather than waiting for one to complete and then the other.
# 6  
Old 04-02-2015
You could open both at once, perhaps, using open() instead of backticks. How about this:

Code:
open(CMD1, "./ssh_run_cmd2.exp xxx.xxx.xxx.xxx $log "show association peer-address $ip", "-|");

open(CMD2, "./ssh_run_cmd2.exp xxx.xxx.xxx.xxx $log "show association peer-address $ip", "-|");

while($line=<CMD1>) { chomp($line); ... }
while($line=<CMD2>) { chomp($line); ... }

close(CMD1);
close(CMD2);

It doesn't read from them from the same time, but if the amount of data is smaller than 64 kilobytes, buffering should let the network communication happen simultaneously anyway. When you finish one, data may already be waiting for you on the second.

The chomp is to remove linefeeds and such, since unlike backticks open() doesn't do that for you. You just get a stream.

Running a handful of these at once is fine. Trying to run hundreds at once is not recommended.
This User Gave Thanks to Corona688 For This Post:
mutley2202
# 7  
Old 04-02-2015
Thanks Corona688
where would I put the regex that you can see from my initial code based on your previous advice.

You advised to try the below however where would i put my expressions shown in the 2nd code box below (this regex is just for the first command one also exists for the second.

Code:
open(CMD1, "./ssh_run_cmd2.exp xxx.xxx.xxx.xxx $log "show association peer-address $ip", "-|");

open(CMD2, "./ssh_run_cmd2.exp xxx.xxx.xxx.xxx $log "show association peer-address $ip", "-|");

while($line=<CMD1>) { chomp($line); ... }
while($line=<CMD2>) { chomp($line); ... }

close(CMD1);
close(CMD2);

Code:
{
                if (/^\s+ID       : (\S+)/) {
                        $ID = $1;
                        $peerfound = 'YES';
                } elsif (/(No matching peer)\S+/) {
                        $peerfoundoutcome = "$1"
                } elsif (/\S{7}(\S+)\s/) {
                        $hostname = $1;
                        }
                }



Thanks again
Last edited by mutley2202; 04-03-2015 at 04:47 AM.. Reason: more info added
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