In Bash, you can find out the exit code of each piped command by checking the exit code of the last command in the pipe. To do this, you can use the special shell variable $? which contains the exit code of the last executed command. For example, consider the following command: command1 | command2 … Read more

To update a Debian or Ubuntu Linux container (LXC) virtual machine, you can use the following steps: Log in to the container: lxc exec container-name bash Update the package list: sudo apt-get update Upgrade all installed packages: sudo apt-get upgrade Upgrade the distribution to the latest version: sudo apt-get dist-upgrade Remove any unused packages: sudo … Read more

To find the WiFi password on Mac OS X, follow these steps: Open the Keychain Access application, which can be found in the Applications > Utilities folder. Search for the network name in the search bar and select the network from the list. Right-click (or Control-click) on the network name and select “Get Info”. In … Read more

To install the Suhosin PHP extension on Debian 8 and Ubuntu 14.04 LTS, you need to perform the following steps: Add the PPA repository for Suhosin: sudo add-apt-repository ppa:ondrej/php Update the package list: sudo apt-get update Install the Suhosin extension: sudo apt-get install php-suhosin Restart the Apache web server: sudo service apache2 restart Verify the … Read more

You can temporarily clear environment variables in the Bash shell on a Linux or Unix-like system by using the following command: env -i bash –norc –noprofile This will start a new instance of the Bash shell with a clean environment, without any environment variables set. The -i option specifies that the environment should be cleared, … Read more

In Linux and Unix-like operating systems, you can run a cron job on the last day of the month by using the following syntax in your crontab file: 59 23 28-31 * * [ “$(date +\%d -d tomorrow)” == “01” ] && /path/to/script This cron job will run on the 28th, 29th, 30th, and 31st … Read more

In FreeBSD, you can add a user to the “wheel” group using the pw command. The “wheel” group is a special group in FreeBSD that has the ability to run the su command to switch to the root user. Here’s how: Add the user to the “wheel” group: sudo pw groupmod wheel -m username Replace … Read more

In Ubuntu, you can use the ufw (Uncomplicated Firewall) tool to open a specific port. Here’s how: Install ufw if it’s not already installed: sudo apt-get update sudo apt-get install ufw Enable the firewall: sudo ufw enable Allow incoming traffic on the desired port: sudo ufw allow port_number Replace port_number with the actual port number … Read more

To make a folder (also known as a directory) in Linux or Unix, use the mkdir command. For example: mkdir folder_name This will create a new folder named folder_name in the current working directory. You can also specify the path where you want to create the folder. For example: mkdir /path/to/folder_name Note: Replace folder_name and … Read more

The dd command can be used to test disk I/O performance on Linux and Unix systems. Here’s an example of how to use it: Create a test file with a specified size and block size: dd if=/dev/zero of=testfile bs=1M count=1024 This creates a file named “testfile” of 1 GB (1024 MB) in size, with a … Read more