Category Archives: Linux (Ubuntu/CentOS)

After installing Ubuntu on VirtualBox… (Guest Additions in Virtual Box)

Virtual Box for some reason doesn’t seem to show Ubuntu in full screen mode and the display is distorted. You will have to install virtualbox-guest-additions in order to fix this issue. First, make sure you have the DKMS (Dynamic Kernel Module Support) package. In a terminal window type: Code: sudo apt-get install dkms Then, install theContinue reading “After installing Ubuntu on VirtualBox… (Guest Additions in Virtual Box)”

iperf (tool to measure the bandwidth and the quality of a network link)

Iperf is a tool to measure the bandwidth and the quality of a network link. The network link is delimited by two hosts running Iperf. The quality of a link can be tested as follows: – Latency (response time or RTT): can be measured with the Ping command. – Jitter (latency variation): can be measured with an IperfContinue reading “iperf (tool to measure the bandwidth and the quality of a network link)”

Linux (Users, Groups and Permissions)

:::::::::::::Users in linux :::::::::::::: (to add a user) fali@ubuntu:~$sudo adduser ali (to delete user) fali@ubuntu:~$sudo userdel ali (to delete user and the user home directory) fali@ubuntu:~$sudo userdel -r ali (to manually delete the user home directory if it is left behind) fali@ubuntu:~$sudo rm -r /home/ali (all user informatin is stored in a text file /etc/passwd)(usersContinue reading “Linux (Users, Groups and Permissions)”

TCPDump Packet Sniffing on Linux Back track 5

tcpdump is a common packet analyzer that runs under the command line. It allows the user to intercept and display TCP/IP and other packets being transmitted or received over a network to which the computer is attached.  Tcpdump prints the contents of network packets. It can read packets from a network interface card or from a previously created saved packet file. Tcpdump canContinue reading “TCPDump Packet Sniffing on Linux Back track 5”

Unix vs. Linux (Difference)

Difference Between Linux and UNIX What is the difference between Linux and UNIX operating systems? UNIX is copyrighted name only big companies are allowed to use the UNIX copyright and name, so IBM AIX and Sun Solaris and HP-UX all are UNIX operating systems. The Open Group holds the UNIX trademark in trust for the industry, andContinue reading “Unix vs. Linux (Difference)”