You can run a command when you log out of a Linux session by using a shell script that is executed by the logout process. There are different methods for executing a script on logout, depending on the shell you are using. For the bash shell: Create a shell script with the commands you want … Read more

You can change the timezone on a CentOS 6 and 7 system using the following steps: Determine the correct timezone: timedatectl list-timezones This will display a list of available timezones. Look for the timezone you want to use and make a note of its name. Change the timezone: sudo timedatectl set-timezone <Timezone_Name> Replace <Timezone_Name> with … Read more

To configure a network interface on a pfSense system as a bridge or network switch, follow these steps: Log in to the pfSense web interface. Go to Interfaces > (assign). Click the plus sign (+) to add a new interface. Select the type of interface you want to create, such as “Bridge”. Give the interface … Read more

You can use the following command to find information about the CPU on a Red Hat Linux (RHEL) system: lscpu This command provides a detailed report of the CPU architecture, including the number of processors, cores, and threads, clock speed, cache size, and other information. You can also use the /proc/cpuinfo file to get information … Read more

Adding swap on a FreeBSD Unix system is a straightforward process that can be done using the following steps: Create a swap file: sudo dd if=/dev/zero of=/swapfile bs=1M count=1024 This creates a file called “/swapfile” with a size of 1024 MB. You can adjust the size of the file as needed by changing the value … Read more

To patch and protect a Linux server against the Glibc GHOST vulnerability (CVE-2015-0235), you need to upgrade the glibc package to a version later than 2.18. The exact steps for upgrading glibc may vary depending on your Linux distribution and the package management system used. Here are the steps for some of the most common … Read more

The GHOST vulnerability is a critical vulnerability that affects the GNU C Library (glibc) versions prior to 2.18. To test if a Linux server is secure and not vulnerable to GHOST, you can use the following command: env ‘x=() { :;}; echo vulnerable’ ‘BASH_FUNC_x()=() { :;}; echo vulnerable’ bash -c ‘echo hello’ If the output … Read more

You can check the version of KVM (qemu-kvm) installed on a Linux system by using the following command: kvm –version or qemu-kvm –version This will print the version number of the installed KVM (qemu-kvm) package. The output should look something like this: QEMU emulator version 4.2.0 (Debian 1:4.2-2ubuntu2) Copyright (c) 2003-2021 Fabrice Bellard and the … Read more

You can perform a stress test on your CPU and memory (in a virtual machine) on a Linux/Unix system using the stress-ng tool. stress-ng is a stress testing tool that can be used to test various aspects of a Linux/Unix system, including the CPU and memory. To stress test the CPU, you can use the … Read more

On Linux, you can check BIOS settings from the command line by using the dmidecode utility. dmidecode is a tool that retrieves information from the system’s BIOS and reports it in a human-readable format. To check the BIOS settings, you can use the following command: sudo dmidecode -t 0 This will display a summary of … Read more