You are using a Postfix mail server, and your system started sending masses of spam emails? The following guide will show you how to narrow down how spam is sent by inspecting emails in the mail queue. To use the postcat command in Postfix to find out who has sent an email that is currently ... Read more
In this short guide, I will show you how to write a PHP function that takes an associative array of key-value pairs as a function parameter and writes its contents to a .env file. Convert an PHP Array to .env file The function has two parameters: the first is the path to the .env file, ... Read more
To check if a file is empty in a Bash script, you can use the "-s" test, which returns true if the file exists and has a size greater than zero. If you want to check if a file is empty, you would use the "!" (not or negate) operator with "-s" to negate the ... Read more
You can use the following script to create a directory like /home/user in a Bash script only if it does not already exist. This script checks if the directory exists, and if not, it creates it: #!/bin/bash # Define the directory path DIR="/home/user" # Check if the directory does not exist if [ ! -d ... Read more
Indenting lines in a file using PHP code is quite easy. The steps are: Open the file and read its contents line by line. For each line, prepend the desired amount of indentation (like spaces or tabs). Write the indented lines back to the file or to a new file. Here's the PHP script: <?php ... Read more
To redirect both the output and the errors of a Bash command to /dev/null, you can use the following syntax: command > /dev/null 2>&1 Here's what this command does: ">" is the redirection operator. It redirects the standard output (stdout) of "command" to a specified file. In this case, the file is "/dev/null". "/dev/null" is ... Read more
To check if a file is empty using PowerShell in Windows, you can use the following command: if ((Get-Item 'path\to\your\file.txt').length -eq 0) { Write-Host "The file is empty." } else { Write-Host "The file is not empty." } Replace 'path\to\your\file.txt' with the actual path to your file. This command checks the length of the file. ... Read more
You need root privileges to empty the root user's crontab on Linux. You can achieve this by either logging in as the root user or using `sudo` if your user has sudo privileges. The crontab can be emptied (i.e., all cron jobs for the root user can be deleted) by running the following command: sudo ... Read more
Exception handling in PHP is a mechanism that allows you to deal with unexpected conditions (like runtime errors) in a program's flow in a clean and manageable way. It uses the try, catch, and throw statements to handle exceptions. To write robust, error-resistant applications, it is crucial to understand and correctly implement exception handling in ... Read more
At the time of writing this in December 2023, the list() function in PHP is not deprecated. This function is commonly used to assign a list of variables in one operation from an array. It's a convenient way to extract multiple values from an array and assign them to individual variables. Here is a short ... Read more