08-17-2008
Grabbing variables and comparing
I have two computers with dynamic IP addresses and am using dyndns so that they are identifiable as the same computer even if their IPs change (we'll call them host1.dyndns.com and host2.dyndns.com). I also have a remote server which I would like to store my computers' IP addresses on. There is a file on my remote server which has the IPs that the two hostnames point to. So the file would look like this
111.111.111.111 #host1.dyndns.com
222.222.222.222 #host2.dyndns.com
I need a script that will run this command which gets the IPs of my computers:
/usr/bin/dig +short host1.dyndns.com | /usr/bin/tail -n 1
/usr/bin/dig +short host2.dyndns.com | /usr/bin/tail -n 1
Then compare the result (which is an IP address) to the file that I have described above. If the IP is different from the old one then remove that line and replace it with the new IP. I thought I could do this myself but grabbing the old IP and storing it in a variable and then comparing it to the new IP was beyond me. I don't even know if that is how you should do it. sed/awk is preferable but any language will do
Thanks in advance.
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LEARN ABOUT REDHAT
amoverview
AMOVERVIEW(8) System Manager's Manual AMOVERVIEW(8)
NAME
amoverview - display file systems processed by Amanda over time
SYNOPSIS
amoverview [[ -config ] config ] [ [-hostwidth width] ] [ [-diskwidth width] ] [ -verbose ]
DESCRIPTION
Amoverview displays a chart showing hosts and file systems processed by Amanda along with the backup level performed each day.
See the amanda(8) man page for more details about Amanda.
OPTIONS
[-config config]
Use configuration config instead of DailySet1.
[-hostwidth width]
Set host field column width to width characters instead of eight.
[-diskwidth width]
Set disk field column width to width characters instead of 20.
-verbose
Amoverview can take a long while on large systems. This option reports intermediate steps while it is working.
EXAMPLE
This shows the /home file system on host2 was backed up at level 3 on the 8th, 9th and 10th of December, had a full backup on the 11th, a
level 1 on the 12th and a level 2 on the 13th.
# amoverview
date 12 12 12 12 12 12
host disk 08 09 10 11 12 13
host1 / 0 1 1 1 1 1
host1 /var 0 1 1 1 1 1
host2 / 1 1 1 1 1 0
host2 /home 3 3 3 0 1 2
host2 /opt 1 1 1 1 1 1
host2 /var 1 1 0 1 1 1
SEE ALSO
amadmin(8), amanda(8)
AMOVERVIEW(8)