extraction of hostnames in hostfile

[grk]

Hi Guru's,

If i have file /hosts and then inside it

10.10.0.1 host1.new.corp.com
10.20.0.1 rts.new.corp.com

say i wan to extract only

host1.new.corp.com
rts.new.corp.com

two hostnames check if alive with ping and then run a rsh command to
check if df of these two machines are >90% or not, how best i can
achive this.

i have script which actually makes use of a file which i actually
prepare by going to hosts file and then updating very often. so if i
can get it direclty from hosts file and do that would save a lot fo
time.
thx for perl gurus in advance.

grk

 

[Josef Moellers]

Hi Guru's,

If i have file /hosts and then inside it

10.10.0.1 host1.new.corp.com
10.20.0.1 rts.new.corp.com

say i wan to extract only

host1.new.corp.com
rts.new.corp.com

two hostnames check if alive with ping and then run a rsh command to
check if df of these two machines are >90% or not, how best i can
achive this.

i have script which actually makes use of a file which i actually
prepare by going to hosts file and then updating very often. so if i
can get it direclty from hosts file and do that would save a lot fo
time.

So: what have you tried so far and where did it not work?
From your description, it is not very clear what exactly your problem
is, so: post some code and we can be of help.

 

[Tad McClellan]

If i have file /hosts and then inside it

10.10.0.1 host1.new.corp.com
10.20.0.1 rts.new.corp.com

say i wan to extract only

host1.new.corp.com
rts.new.corp.com

perl -lane 'print $F[1]' /hosts

two hostnames check if alive with ping and then run a rsh command to
check if df of these two machines are >90% or not, how best i can
achive this.

There are 3 ways of executing external programs, described in
the answer to this Perl FAQ:


How can I capture STDERR from an external command?

 

[Tintin]

Hi Guru's,

If i have file /hosts and then inside it

10.10.0.1 host1.new.corp.com
10.20.0.1 rts.new.corp.com

say i wan to extract only

host1.new.corp.com
rts.new.corp.com

two hostnames check if alive with ping and then run a rsh command to
check if df of these two machines are >90% or not, how best i can
achive this.

i have script which actually makes use of a file which i actually
prepare by going to hosts file and then updating very often. so if i
can get it direclty from hosts file and do that would save a lot fo
time.
thx for perl gurus in advance.

Much better job for a shell script

#!/bin/sh
for host in `awk '{print $2}' /etc/hosts`
do
if ping -c1 $host >/dev/null 2>&1
then
df=`rsh $host df /whateverfilesystem | tail -1 | awk '{print $5}' |
sed 's/%//'`
if [ $df -gt 90 ]
then
echo "filesystem greater than 90% capacity"
fi
fi
done

Note that ping and df options will vary depending on your Unix flavour.

Of course, you could write the equivalent in Perl, but you'd either have to
use a number of modules, or use a whole bunch of system calls, which would
pretty much defeat the purpose of writing it in Perl in the first place.