The Linux “top” command is often the go to tool for system administrators who need to check on the health of a system. It displays essential system information like CPU load, memory usage, swap usage and a list of the top processes on one convenient, live screen. While “top” is good, there are also some … Read more
Since its first release in 2004, Ubuntu has grown to become a driving force among the popular Linux distributions. From giving away free CDs (before broadband was widely available) to its long-term support releases, Ubuntu has often caused a stir. For some, it is the user interface that causes a problem. Where is GNOME? Where … Read more
We have shown you before how you can can find out the download speed of your Internet connection from the terminal, but that only gives you the download speed. If you want to know about the upload speed as well, speedtest-cli is yet another tool you can use. Speedtest-cli is a python script for testing … Read more
Optical media might have lost their prominence to other portable storage mediums like USB pen drives, but they still have their uses. DVDs figure in my backup rotation policy for housing files that are over a year old. They are also a good medium to store a bare-metal image of a fully-setup machine. But optical … Read more
We have seen in the first two parts of this series (a beginner’s guide to using nmap and advanced uses for nmap) that nmap is a powerful, yet easy to use, tool for network discovery and service enumeration. However, like many command line tools, the wealth of information can sometimes be overwhelming and maybe difficult … Read more
One of the attractive things about the Raspberry Pi (besides its price and capabilities) is that it can run several different flavors of Linux and even other non-Linux based operating systems like RISC OS. Each of these operating systems has their own SD card image file available. To experiment with the different OSes, this means … Read more
nmap is a network scanning tool which can be used for a whole variety of network discovery tasks including port scanning, service enumeration and OS fingerprinting. To install nmap on Ubuntu or Raspbian use: sudo apt-get install nmap For Linux versions that use yum, like Fedora, run this as root: yum install nmap The simplest … Read more
Following on from the first part in this series, it is time to look at some of the more advanced features of nmap. Starting with the basic port scan, it is possible to get more information about the scan by adding the -vv flag: nmap -vv 192.168.1.101 The output will look something like this: In … Read more
If you have used SSH to connect to a remote machine before, you know the procedure: open a terminal, type in the SSH command and the host IP, enter the password. This is probably easy for a single connection, but if you are a system administrator looking after several remote machines and have a need … Read more
No matter how fast your Linux machine is, there will always be some tasks that consume lots of CPU time. Everything from video encoding to running mathematical models can cause the CPU to run at 100%. This is fine if the machine isn’t doing anything else. But if it is your main desktop or it … Read more