shell script (bind related)

OTIM · 07-10-2008, 11:42 AM

Hello,

I made a shell script which assignes a reverse to an ip , using sed
The problem is that i don't know how to increment the serial after i make the changes.
i mean each time i run the script to also increment the serial
I have the reverse file like this :
$ORIGIN .
$TTL 86400 ; 1 day
<something>.IN-ADDR.ARPA IN SOA ns.domain.com. root.domain.com (
2006101900 ; serial
10800 ; refresh (3 hours)
15 ; retry (15 seconds)
172800 ; expire (2 days)
86400 ; minimum (1 day)
)

I need the script to increment the serial 2006101900 lets say to 2006101901

Thank you

unSpawn · 07-10-2008, 12:29 PM

You can use "n=2006101900; n=$[$n+1]; echo $n" or "n=2006101900; let n=$n+1; echo $n" or "n=2006101900; ((n++)); echo $n" or "n=2006101900; n=$(echo "$n + 1"|bc -l); echo $n".

OTIM · 07-10-2008, 12:41 PM

hello,

Thank you for your reply. The problem is not that simple, because i don't know the value of the serial number; this value can change over time when people modify the file.
I need the script to somehow extract that value increment it and replace the old value with the new one

ntubski · 07-10-2008, 01:33 PM

Code:

 
n=$(sed -n 's/[ \t]*\(.*\) ; serial/\1/p' reverse-file)
let n=$n+1 # or one of the others...
sed -i "s/.* ; serial/      $n ; serial/" reverse-file

unSpawn · 07-10-2008, 01:33 PM

Not knowing the value is not a problem. As long as one record template version is used you can grep for any markers in use. For instance considering the record

Code:

example.com.  IN      SOA   ns.example.com. root.example.com. (
                              2006101900 ; se = serial number
                              3h         ; ref = refresh
                              15m        ; ret = update retry
                              3w         ; ex = expiry
                              3h         ; min = minimum
                              )
                  IN      NS      ns1.example.com.
                  IN      NS      ns2.example.com.
                  IN      MX  10  mail.example.com.
; public hosts
ns1             IN      A       192.168.254.1
ns2             IN      A       192.168.254.2
mail            IN      A       192.168.254.3
www           IN      A       192.168.254.4
ww1           IN      A       192.168.254.5
; private hosts 
abaddon     IN      A       192.168.254.6
abdiel         IN      A       192.168.254.7
abraxas      IN      A       192.168.254.8
accounting  IN      A       192.168.254.9

something like " awk '/(serial|se|200[0-9].*

/ {print}' " should get you the value to work with, else use a better regex or post a properly anonimised example record.

Mr. C. · 07-10-2008, 03:08 PM

I assume you want to bump the serial number, using the common date/revision formatting practice. So a bump should change the date to today's date, not just increment by one.

The following sets the serial number date to today's date + revision number. Note: it will fail after 99, as the general serial number update scheme with a date fails there anyway.

Code:

$ cat bump_serial.sh
#!/bin/bash

perl -i.bak -pe 'BEGIN {chomp ($now=qx/date +%Y%m%d/)};
    /(\d{8})(\d{2})/ and do {
        $serial = ($1 eq $now ? $2+1 : 0);
        s/\d{8}(\d{2})/sprintf "%8d%02d",$now,$serial/e;
}' zonefile

$ bump_serial.sh

$ diff zonefile zonefile.bak
5c5
< 2008071000 ; serial
---
> 2006101902 ; serial
13c13
<                               2008071000 ; se = serial number
---
>                               2006101900 ; se = serial number
35c35
<                               2008071035 ; se = serial number
---
>                               2008071034 ; se = serial number

Use the perl statement inside your shell script. Replace "zonefile" with the variable or zone file you use in your script. It automatically creates a backup file too.

OTIM · 07-10-2008, 04:26 PM

Thank you very much friends.