You can check if a variable is defined in a bash script by using the “if [ -z ${var} ]” or “if [ -v var ]” command. For example, if you want to check if a variable named “var” is defined, you can use: if [ -z “${var}” ]; then echo “var is not defined” … Read more
bhyve is a hypervisor for FreeBSD that allows you to run virtual machines (VMs) on top of a FreeBSD host. You can use bhyve and ZFS to install a Linux VM on a FreeBSD host. Here are the general steps to do this: Create a ZFS pool on the host system: zpool create -f mypool … Read more
Homebrew is a package manager for Mac OS that allows you to easily install and manage software packages. To install Homebrew on Mac OS, you can use the following steps: Open the Terminal application on your Mac. Run the following command in the terminal to install Homebrew: /bin/bash -c “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/main/install.sh)” Once the installation … Read more
Homebrew is a package manager for Mac OS that allows you to easily install and manage software packages. To install Homebrew on Mac OS, you can use the following steps: Open the Terminal application on your Mac. Run the following command in the terminal to install Homebrew: /bin/bash -c “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/main/install.sh)” Once the installation … Read more
ShellCheck is a static analysis tool for shell scripts that helps to identify and fix common issues and errors. You can install ShellCheck on FreeBSD using the package manager pkg. First, ensure that the package manager is updated by running the command: pkg update Next, install ShellCheck by running the command: pkg install shellcheck Once … Read more
In awk, you can force it to not print a newline at the end of the output by using the “ORS” variable. This variable controls the output record separator and by default, it is set to a newline character. You can set the ORS variable to an empty string to prevent awk from printing a … Read more
On Alpine Linux, you can configure a static IP address by editing the network configuration files. To view the current network configuration, you can use the command ip a or ifconfig. To configure a static IP address, you need to edit the network configuration file located at /etc/network/interfaces. You can use a text editor such … Read more
On Alpine Linux, you can view the CPU temperature using the “sensors” command, which is a command-line utility for monitoring the temperature of various hardware components. To view the CPU temperature, you need to first install the “lm_sensors” package by running the following command: apk add lm_sensors Once the package is installed, you can use … Read more
On Linux systems that use systemd, it may be necessary to restart systemd without rebooting the entire system. This can be done by reloading the systemd manager configuration and restarting the systemd-journald and systemd-udevd services. First, check the status of systemd-journald and systemd-udevd services by running the following command: systemctl status systemd-journald systemd-udevd Next, reload … Read more
vnStat is a command-line tool that can be used to monitor and track network traffic on Alpine Linux. You can install vnStat on Alpine Linux using the package manager apk. To install vnStat, you need to run the following command: apk add vnstat To start the vnStat daemon and make it start automatically at boot … Read more