Category: Unix

Unix

How To Tell If Your Linux Server Has Been Compromised

A server being compromised or hacked for the purpose of this guide is an unauthorized person or bot logging into the server in order to use it for their own, usually negative ends. However, the majority of compromised servers are carried out by bots i.e. automated attack programs, in-experienced attackers e.g. “script kiddies”, or dumb criminals. These sorts of attackers will abuse the server for all it’s worth whilst they have access to it and take few precautions to hide what they are doing.

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How to effectively use the GREP command

Grep is a very important & powerful Linux commands. It stands for ‘Global Regular Expression Print’ & is used for matching & printing a search pattern or a regular expression from a single or multiple text files. It will look for the pattern if the mentioned files & will than print the result on screen or to an output file.
In this tutorial, we are going to learn to use grep command with examples. Continue reading “How to effectively use the GREP command”

bash Tips and Tricks

I call these tips and tricks – “bash kung-fu”. You can save a lot of typing with these handy bash features.

bash, or the Bourne again shell, is the default shell in most Linux distributions. It has many features to enhance user-friendliness and productivity. Unfortunately, you can’t take advantage of those features unless you know they exist. So here are some bash tips and tricks that will help you with your everyday system admin tasks.
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How to find out PID in Linux

Every Linux process has a process ID (PID) assigned to it.  It is a unique identification number that is automatically assigned to each process when it is created in an operating system. A process is a running instance of a program. In this tutorial we’ll look into ways on how to find the PID of process.

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USB Ports and Versions Explained

Universal Serial Bus, more commonly known as the USB has been around for quite some time now with almost every device following the standard. From our I/O devices to storage drives and even mobile phones can be connected using the USB standard. USB ports version will be explained below

This standard has evolved over the years from its inception in the mid 90’s and has had multiple versions through its history.

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Recover disk usage after deleting large file in Linux

Disks getting full on Linux is a common scenario any administrator have probably experienced. There are usually some large files in /var/log directory that can be compressed or deleted to save disk space. Have you ever experienced deleting a large log file and noticed that the disk usage remained the same ? It’s as if the file size usage is not released even though you’ve deleted it?

This scenario can happen if you deleted/renamed/moved an existing file that is currently in use by a running program. This usually happens on log files that are not rotated regularly and then when the file size becomes large, you deleted (or compressed) the file without even checking if it is in-use. Don’t worry, you can still recover your disk space as shown from the example below.

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