UNIX for Dummies Questions & Answers

Hi.
I hope someone can help me. I have e very special question.
I have a Lunix server and I have installed Webmin on it. This way, I can create a login for an other user and give him restricted access to some custom commands I set up.
One of the commands i would like to setup, is for him to change the ip adress. With Webmin, I have the option to edit files en perform commands afterwards, so my first thought was to edit the ifcfg-eth'x' file (x because i have several network cards). But the file contains too much data, for I want him to only be able to change the IP-adress, Netmask and Gateway (of 1 of the cards).
Standard it looks something like this:

# Intel Corporation 80003ES2LAN Gigabit Ethernet Controller (Copper)
DEVICE=eth0
BOOTPROTO=none
BROADCAST=192.168.101.255
IPADDR=192.168.101.91
IPV6INIT=no
IPV6_AUTOCONF=yes
NETMASK=255.255.255.0
NETWORK=192.168.101.0
ONBOOT=yes
GATEWAY=192.168.101.1
TYPE=Ethernet
PEERDNS=yes
USERCTL=no

when actually I would only need something like this:

IPADDR=192.168.101.91
NETMASK=255.255.255.0
GATEWAY=192.168.101.1

Is there a way to link the original file to a new file, and when they edit teh new file, because of the link the original file will also be edited (the identical lines as IPADDR etc), and after which i give the command to restart the network devices, which allows the user to change only the given data in that new file, and so make him activate these new settings.

I hope I was clear enough; I know its something strange, but i need it in a very specific service.

thanks in advance!

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Maybe a solution via sudo for the needed commands can do.
But what "normal" user should be able to change IP-addresses?

Whatever - you could set up something like an "exchange" directory where the use has permissions to edit the file and via cron it will replace the original file which has been backed up before of course and then issue a network restart.

First of all, sorry for the mess I might have made in the previous post (Newbie :s) and thanks for the reply!!

This is going to be an ip video server, so you can understand the actual 'user' has to be able to change the ip address.

Now this looks like something I have been looking for. How do I make such an 'exchange' directory? And how do I link the new file with the original file? (or some data in the new file)?

The main idea is I am and remain the root, but the user can control some settings and do some commands, without becoming root or even log in to linux.

Thanks in advance!

You create a group for these users and assign them to it. You create a directory where the file to be changed is placed in, lets say

Code:

/usr/local/var/vid_ipconf.txt

which is a copy of your ip config file.
chgrp the directory and the file so that the group you created can access and write to both, the directory and the file.

As next write a small shell script, that does a copy of the original file that will be placed under /etc/network.... (whereever your original config file is placed) each time the script is run. So a simple

Code:

cp -p /etc/network/origfile /origfile.bk

will do maybe.
Next this script copies the file placed the exchange directory (/usr/local/var/vid_ipconf.txt) over the original config file (/etc/network/origfile) and you have to restart your network (?? /etc/init.d/network restart).

This script should be placed into the crontab of root so that it will be called every interval you configure.

I hope the picture got sharper

Make sure you try out before you do so not that you loose connect entirely. No idea if you are remote connected to that machine or can access it via keyboard and screen locally if something goes wrong.

Thanks!!!

That looks great! I'm gonna try that, but it is going to be for monday.
I am locally connected to the server, so it's no problem if something should change.
I will let you know if it worked.

Thank you!

I'm a bit lost...

i get the theoretical part of your explanation, but it's the practical part where it al goes wrong
I have made the new file. Created a user(group).
The little shell script that makes the backup, that's ok to.
But then I get stuck. How do i create the script that copies the lines in the new file over the lines in the old file, without copying the whole file (lines like it's mac address can not be changed)? And can you explain me the part about the contrab, cause that's something I never heard before.
Sorry to keep bothering you..

Cron:
https://www.unix.com/answers-frequent...n-crontab.html

Changing parts of the file; note that I have put another IP address into the "change" file so you notice the difference:

Code:

$> cat orig
# Intel Corporation 80003ES2LAN Gigabit Ethernet Controller (Copper)
DEVICE=eth0
BOOTPROTO=none
BROADCAST=192.168.101.255
IPADDR=192.168.101.91
IPV6INIT=no
IPV6_AUTOCONF=yes
NETMASK=255.255.255.0
NETWORK=192.168.101.0
ONBOOT=yes
GATEWAY=192.168.101.1
TYPE=Ethernet
PEERDNS=yes
USERCTL=no
$> cat change
IPADDR=192.168.101.33  <----------------- here is a different number so you notice the difference?!
NETMASK=255.255.255.0
GATEWAY=192.168.101.1
$> awk -F"=" 'NR == FNR {_[$1]=$0; next} _[$1] {print _[$1]; next} $0' change orig
# Intel Corporation 80003ES2LAN Gigabit Ethernet Controller (Copper)
DEVICE=eth0
BOOTPROTO=none
BROADCAST=192.168.101.255
IPADDR=192.168.101.33
IPV6INIT=no
IPV6_AUTOCONF=yes
NETMASK=255.255.255.0
NETWORK=192.168.101.0
ONBOOT=yes
GATEWAY=192.168.101.1
TYPE=Ethernet
PEERDNS=yes
USERCTL=no