Perl - open a CLI environment and send commands

Question

i'm new with Perl :)

i'm trying to write a simple script just open a CLI environment ( by executing bash command) and then send a command to that environment (only that environment familiar with this command)

for example: my linux is running in HP server machine. if i would like to see the memory configuration so under root user i need to execute: 'hpasmcli" and then i well get the following environment :

NOTE: Some hpasmcli commands may not be supported on all Proliant servers.

Type 'help' to get a list of all top level commands.

hpasmcli>

and now the need to enter "show dimm":

NOTE: Some hpasmcli commands may not be supported on all Proliant servers.

Type 'help' to get a list of all top level commands.

hpasmcli> show dimm

then i will get the memory configuration in the server.

so i'm tying to write a Perl script to make this simple task. i tried to use "expect" and "open(FH,"|/sbin/hpasmcli") but i was able just to log in to the CLI environment and not to send the command "show dimm"

Thank you for your help!

check out kudos.be/hppro_hw_monitor

mpapec
– mpapec

2013-07-21 08:53:14 +00:00
Commented Jul 21, 2013 at 8:53 — mpapec
– mpapec, Commented Jul 21, 2013 at 8:53

7stud · Accepted Answer · 2013-07-21 09:16:56Z

1

You might need to flush the output buffer after every write:

open my $CMD, "| /sbin/hpasmcli"
    or die "Couldn't pipe output to hpasmcli: $!";


my $old_out = select $CMD;
$| = 1;    #perl's autoflush global variable which affects the current output file handle
select $old_out;

print {$CMD} "show dimm";

edited Jul 21, 2013 at 9:16

answered Jul 21, 2013 at 9:06

7stud

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3 Comments

Asfbar Over a year ago

Thank you. i tried it but i got the same result as i used open(FH,...") it just log in to the CLI environment but not send the second command.

7stud Over a year ago

Try something simpler first: see if you can pipe some output to the cat command.

salva Over a year ago

probably, you need to add the end of line marker \n to the command: print {$CMD} "show dimm\n";

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