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clean /etc/hosts

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# 1  
Old 11-06-2006
clean /etc/hosts
hi all,
i need to write a script. it should be able to clean the /etc/hosts file like this:

first field is the ip (what else Smilie)
second field is the fqdn (full qualified domain name)
third field is the hostname

the fourth to n'th field is the rest.

i hope you understand what is needed?

tia,
DN2

btw. i use solaris to run the script. so there is no gawk only (n)awk!
Last edited by DukeNuke2; 11-07-2006 at 04:17 AM..
# 2  
Old 11-06-2006
so, there are ways to do this in perl ( open the file for writing ) and replace the respective strings using regexp.
# 3  
Old 11-07-2006
What kind of cleaning do you want to do ?
Show us an example please.


Jean-Pierre.
# 4  
Old 11-07-2006
Quote:
Originally Posted by aigles
What kind of cleaning do you want to do ?
Show us an example please.


Jean-Pierre.
o.k.:
the file looks like this:

192.168.0.100 hostname alias anotheralias hostname.mydomain.com

and should look like this

192.168.0.100 hostname.mydomain.com hostname alias anotheralias (and so on for every other alias)
# 5  
Old 11-07-2006
The following awk program clean the /etc/hosts file :
Code:
#! /usr/bin/awk -f
NF>0 && $1 !~ /^#/ {

   comment    = "";
   ip         = $1;
   host_alias = "";
   fqdn       = "";

   if (match($0, /#/)) {
      comment = substr($0, RSTART);
      $0      = substr($0, 1, RSTART-1);
   }

   for (i=2; i<=NF; i++) {
      if ($i ~ /.*\..*\..*/)
         fqdn = (fqdn ? fqdn OFS : "") $i;
      else
         host_alias = (host_alias ? host_alias OFS : "") $i;
   }

   print ip, fqdn, host_alias, comment;
   next;
}
1

Input file :
Code:
#
# /etc/host
#

192.168.0.100 host0 alias0a alias0b host0.mydomain.com
192.168.0.101 host1 alias1a alias1b host1.mydomain.com # Comment for host1
192.168.0.102 host2.mydomain.com host2 alias2
192.168.0.103 host3.mydomain.com host3a hostb host3b.mydomain.com
192.168.0.104 host4
192.168.0.105 host5.mydomain.com

Output:
Code:
#
# /etc/host
#

192.168.0.100 host0.mydomain.com host0 alias0a alias0b 
192.168.0.101 host1.mydomain.com host1 alias1a alias1b # Comment for host1
192.168.0.102 host2.mydomain.com host2 alias2 
192.168.0.103 host3.mydomain.com host3b.mydomain.com host3a hostb 
192.168.0.104  host4 
192.168.0.105 host5.mydomain.com


Jean-Pierre.
# 6  
Old 11-07-2006
wow, fantastic work.... thank you!
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