Hi all
I have spent half a day trying to create a shell script which reads a configuration file on a line by line basis.

The idea of the file is that each will contain server information, such as IP address and various port numbers. The line could also be blank (The file is user created). Here is an example

Code:

$ cat /tmp/servers
172.18.1.1

172.18.50.1 tcp SSH SSL=8443

The script should ignore any empty lines, obviously. For the line with server 172.18.1.1, default settings should be used as nothing else is specified (Default is UDP mode port 500). For the line 172.18.50.1, the specified settings are that tcp mode is to be used, and SSH and SSL on port 8443 options are also to be used.

This is what I have created, as an example. The final product will obviously do much more, it is the reading in of the lines and variables that I need help with.

Code:

#!/bin/sh
cat /tmp/servers | while read SRV ; do
IP=$(grep -o '^[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}' $SRV)
if [ ! -z $IP ] ; then
if grep -i "tcp" $SRV ; then TCP=1 ; fi
if grep -i "udp" $SRV ; then UDP=1 ; fi
if ! grep -i "tcp" $SRV ; then UDP=1 ; fi
SSL=$(grep -i -o 'ssl=[0-9]\{1,5\}' $SRV | cut -d = -f2) ; if [ -z $SSL] ; then if grep -i "ssl" $SRV ; then SSL=443 ; fi ; fi
SSH=$(grep -i -o 'ssh=[0-9]\{1,5\}' $SRV | cut -d = -f2) ; if [ -z $SSH] ; then if grep -i "ssh" $SRV ; then SSH=22 ; fi ; fi
HTTP=$(grep -i -o 'http=[0-9]\{1,5\}' $SRV | cut -d = -f2) ; if [ -z $HTTP] ; then if grep -i "http" $SRV ; then HTTP=80 ; fi ; fi 
echo "$IP $SSL $SSH $HTTP" 
fi ; done

The idea here is that each line will be read in. grep will attempt to find a valid IP address in that line, and if it does ( if [ ! -z $IP ] ) then the line will be checked for all possible options. Otherwise if there is no valid IP address on the line it will go to the next line.

I know that I am going wrong somewhere. I cannot use the $SRV string to get any information, although this pasted script simply gives no response. I also believe that using

Code:

if [ ! -z $SRV ]

will not work with the servers file where the line contains spaces. Is this true?

Can anyone advise on the commands I should be using to read the lines and gain these variables. Could I use a for loop instead?

Thanks for any help

PS also, is the usage of grep ok? I had used awk before but this seems to work ok and be shorter. Is there any advantage of one over the other? Thanks