Script does not want to run in background ?!?

[Benoit Lefebvre]

I made a little script that ssh to many servers (IBM HMCs) to get a
list of all logical partitions on some pSeries servers managed by the
HMCs

Here is the complete script: (It's called getlpars.pl)
-----------------------------------------------------------------------------------------------------------
#!/usr/bin/perl

chomp(@hmclist = `cat ~/scripts/conf/hmc.list`);

foreach (@hmclist) {
my($hmc,$hmctype) = split(":",$_);

if ($hmctype eq "p4") {

chomp(@list = `ssh -q hscroot\@$hmc 'lssyscfg -r sys --all'`);

@managedsystems = ();

for ($i = 1; $i <= scalar @list -1; $i++) {
$system = substr($list[$i],0,16);
$system =~ s/\s*$//g;
push(@managedsystems, $system);
}

foreach (@managedsystems) {
$system = $_;
$system = "\"".$system."\"";

chomp(@list = `ssh -q hscroot\@$hmc 'lssyscfg -m $system -r lpar
--all'`);

for ($i = 2; $i <= scalar @list -1; $i++) {
$lpar = substr($list[$i],0,20);
$lpar =~ s/\s*$//g;
print $hmc .":". $system .":". $lpar . "\n";
}
}
} elsif ($hmctype eq "p5") {
@list = `ssh -q hscroot\@$hmc 'lssyscfg -r sys'`;

@managedsystems = ();

foreach (@list) {
@ln = split(",", $_);
push(@managedsystems, substr($ln[0],5,length($ln[0])));
}

foreach (@managedsystems) {
$system = $_;
$system =~ s/\s/\\ /g;
@list2 = `ssh -q hscroot\@$hmc 'lssyscfg -r lpar -m $system -F --
header`;
foreach (@list2) {
@ln2 = split(",", $_);
print $hmc .":". $system .":". $ln2[0] . "\n";
}
}
}
}
-----------------------------------------------------------------------------------------------------------

~/scripts/conf/hmc.list contains a list of all HMCs with they type (p4
or p5) delemited with ":"

Content of hmc.list
-----------------------------------------------------------------------------------------------------------
name_of_hmc4
name_of_hmc25
-----------------------------------------------------------------------------------------------------------

Here is the "problem"

When I execute the script manually from the shell I get the outputs I
want.

When I run it from the crontab or in background "&" it fails.

[user@server (~/scripts/scripts)]: ./getlpars.pl &
[2] 467196
[2] + Stopped (SIGTTIN) ./getlpars.pl &

Is there any way to get more details on the error.. why it's
stopping ?

Thanks,
--Benoit Lefebvre
(e-mail address removed)

 

[Bill H]

I made a little script that ssh to many servers (IBM HMCs) to get a
list of all logical partitions on some pSeries servers managed by the
HMCs

Here is the complete script: (It's called getlpars.pl)
---------------------------------------------------------------------------­--------------------------------
#!/usr/bin/perl

chomp(@hmclist = `cat ~/scripts/conf/hmc.list`);

foreach (@hmclist) {
my($hmc,$hmctype) = split(":",$_);

if ($hmctype eq "p4") {

chomp(@list = `ssh -q hscroot\@$hmc 'lssyscfg -r sys --all'`);

@managedsystems = ();

for ($i = 1; $i <= scalar @list -1; $i++) {
$system = substr($list[$i],0,16);
$system =~ s/\s*$//g;
push(@managedsystems, $system);
}

foreach (@managedsystems) {
$system = $_;
$system = "\"".$system."\"";

chomp(@list = `ssh -q hscroot\@$hmc 'lssyscfg -m $system -r lpar
--all'`);

for ($i = 2; $i <= scalar @list -1; $i++) {
$lpar = substr($list[$i],0,20);
$lpar =~ s/\s*$//g;
print $hmc .":". $system .":". $lpar . "\n";
}
}
} elsif ($hmctype eq "p5") {
@list = `ssh -q hscroot\@$hmc 'lssyscfg -r sys'`;

@managedsystems = ();

foreach (@list) {
@ln = split(",", $_);
push(@managedsystems, substr($ln[0],5,length($ln[0])));
}

foreach (@managedsystems) {
$system = $_;
$system =~ s/\s/\\ /g;
@list2 = `ssh -q hscroot\@$hmc 'lssyscfg -r lpar -m $system -F --
header`;
foreach (@list2) {
@ln2 = split(",", $_);
print $hmc .":". $system .":". $ln2[0] . "\n";
}
}
}}

---------------------------------------------------------------------------­--------------------------------

~/scripts/conf/hmc.list contains a list of all HMCs with they type (p4
or p5) delemited with ":"

Content of hmc.list
---------------------------------------------------------------------------­--------------------------------
name_of_hmc4
name_of_hmc25
---------------------------------------------------------------------------­--------------------------------

Here is the "problem"

When I execute the script manually from the shell I get the outputs I
want.

When I run it from the crontab or in background "&" it fails.

[user@server (~/scripts/scripts)]: ./getlpars.pl &
[2] 467196
[2] + Stopped (SIGTTIN) ./getlpars.pl &

Is there any way to get more details on the error.. why it's
stopping ?

Thanks,
--Benoit Lefebvre
(e-mail address removed)

Could it be a permissions issue? I had a similar issue with a program
that ran fine on a server from the telnet prompt, but wouldnt in a
cronjob. Worked out I had to "chown" it so it would execute in the
cron job.

Bill H

 

[Benoit Lefebvre]

You're supposed to use `ssh -n` for that.

-n Redirects stdin from /dev/null (actually, prevents reading from
stdin). This must be used when ssh is run in the background.

Oh!

Hey it's working now

Thanks for that.. I feel so stupid to have forgot that !

Thanks!

--Benoit Lefebvre
(e-mail address removed)

 

[John W. Krahn]

I made a little script that ssh to many servers (IBM HMCs) to get a
list of all logical partitions on some pSeries servers managed by the
HMCs

Here is the complete script: (It's called getlpars.pl)

use warnings;
use strict;

chomp(@hmclist = `cat ~/scripts/conf/hmc.list`);

foreach (@hmclist) {

Why fork a shell to cat a file when you can just open it in perl?

open HMCLIST, '<', "$ENV{HOME}/scripts/conf/hmc.list"
or die "Cannot open '$ENV{HOME}/scripts/conf/hmc.list' $!";

my($hmc,$hmctype) = split(":",$_);

if ($hmctype eq "p4") {

chomp(@list = `ssh -q hscroot\@$hmc 'lssyscfg -r sys --all'`);

@managedsystems = ();

my @managedsystems;

for ($i = 1; $i <= scalar @list -1; $i++) {

"scalar @list -1" is the long way of saying "$#list".

$system = substr($list[$i],0,16);
$system =~ s/\s*$//g;

You are using the /g option for a pattern that will only match once (it is
anchored to the end of the string and a string has only one end.) You are
using the * modifier which means that even strings with no whitespace at the
end will be modified. You should use the + modifier instead. Instead of
doing substr() and then substitution you can do both operations with unpack()
(see below.)

push(@managedsystems, $system);
}

for ( @list ) {
push @managedsystems, unpack 'A16', $_;
}

Or doing the declaration and assignment together:

my @managedsystems = map unpack( 'A*', $_ ), @list;

foreach (@managedsystems) {
$system = $_;
$system = "\"".$system."\"";

$system = qq["$_"];

chomp(@list = `ssh -q hscroot\@$hmc 'lssyscfg -m $system -r lpar
--all'`);

for ($i = 2; $i <= scalar @list -1; $i++) {

See above.

$lpar = substr($list[$i],0,20);
$lpar =~ s/\s*$//g;

See above.

print $hmc .":". $system .":". $lpar . "\n";
}

for ( @list ) {
$lpar = unpack 'A20', $_;
print "$hmc:$system:$lpar\n";
}

}
} elsif ($hmctype eq "p5") {
@list = `ssh -q hscroot\@$hmc 'lssyscfg -r sys'`;

@managedsystems = ();

foreach (@list) {
@ln = split(",", $_);
push(@managedsystems, substr($ln[0],5,length($ln[0])));

"substr($ln[0],5,length($ln[0]))" is a long way of saying "substr($ln[0],5))".

push @managedsystems, substr( ( split /,/ )[0], 5 );

}

foreach (@managedsystems) {
$system = $_;
$system =~ s/\s/\\ /g;
@list2 = `ssh -q hscroot\@$hmc 'lssyscfg -r lpar -m $system -F --
header`;
foreach (@list2) {
@ln2 = split(",", $_);
print $hmc .":". $system .":". $ln2[0] . "\n";
}
}
}
}

John