I've used a few techniques for this kind of reading but gets failed until I've read this fine blog . http://www.bashguru.com/2010/05/how-to-read-file-line-by-line-in-shell.html this helps a lot and i have developed a trick for me. Refer to the following example to examine the script : #!/bin/bash #SCRIPT: method2.sh #PURPOSE: Process a file line by line with redirected while-read loop . FILENAME=$1 count=0 while read LINE do let count++ echo "$count $LINE" done < $FILENAME echo -e "\nTotal $count Lines read" I have passed the file in the end of the loop so i didn't need to use pipe that is why i process the file in fastest manner and gives the required output in a quick manner. However i can use one more thing the File Descriptors. The File Descriptors are similar to the normal file pointers however in more analogue way.If you have used C then you will have familier with the the default file openers in C "st...
Allowing users to have ssh access Hi Readers, It is one of the tasks we need to complete in order to allow users to log-in into your server without compromising your security. We are going to accomplish the following tasks, 1.) Allow the users for given domain only 2.) Must allow access to a given domain 3.) Block access for a specific domain. These questions are asked in RedHat certification examination RHCE6 We are going to complete the above mention task using iptables To give proper example we are taking 192.168.20.0/255.255.255.0 as our domain and 192.168.21.0/255.255.255.0 as other domain. Assuming that your system is a fresh installation we can remove all rules previously applied. # iptables -F The above mention command will flush all the previously applied rules. Insert a rule in your input chain by below mention command, # iptables -I INPUT -s <ip of your domain>/<subnet mask> -p <protocal tcp/udp> --dport <port> -...