One of the things that excited me while learning Unix/Linux was how quickly one can perform tasks via the command line. Bash is a fully functional scripting language that incorporates Variables, Loops and If/Then statements; the bash shell allows a user to use these functions while performing adhoc tasks via the command line. This is also true for the other common shells such as bourne, korn shell, and csh.
Below I will show 5 example for loops that are run on the command line without being placed into a shell script.
In a previous article I covered a little bit about Symlinks and Hardlinks but I never really explained what they are or how to create them. Today I am going to cover how to create both Symlinks and Hardlinks and what the difference is between the two.
What are Symlinks and Hardlinks Hard Links In Linux when you perform an listing in a directory the listing is actually is a list of references that map to an inode.
Recently I coveredhow to increase and decrease the CPU priority of processes using nice and renice. Today I am going to cover how to change the default niceness value for a user or group.
Why change the default CPU priority value? Before explaining how to change the default niceness value, let's cover why this could be useful.
Scenario #1 You have a system that has thousands of users that log in via SSH and could potentially run CPU intensive tasks.
Recently I was working on an issue where an application was not retaining the umask setting set in the root users profile or /etc/profile. After looking into the issue a bit it seemed that the application in question only applied the umask setting that was set in /etc/bashrc and would not even accept the values being the applications own start scripts.
After doing a bit of researched I learned a little bit more about what exactly these files do, the differences between them and when they are executed.
For today's article I am going to explain how to create a basic firewall allow and deny filter list using the iptables package. We will be focused on creating a filtering rule-set for a basic everyday Linux web server running Web, FTP, SSH, MySQL, and DNS services.
Before we begin lets get an understanding of iptables and firewall filtering in general.
What is iptables? iptables is a package and kernel module for Linux that uses the netfilter hooks within the Linux kernel to provide filtering, network address translation, and packet mangling.