Author: Rahul

In Bash, you can store the standard error output of a command to a variable by using the `2>&1` operator and the `$()` command substitution syntax. Here `2>` redirects the error message to &1`, that represent to standard output. In the case of bash shell works as the standard output device. For example, to store the standard error output of the `ls` command to a variable named errors, you can use the following command: errors=$(ls non-existent-file 2>&1) Alternatively, you can use the `$?` special parameter to store the exit status of a command to a variable. The exit status is…

Zsh, or the Z Shell, is a powerful and flexible command-line shell for Unix-like operating systems, including Linux and macOS. It offers many features and improvements over the default bash shell, including improved command completion, spelling correction, and customizable prompts. In this article, we will learn how to install and configure Zsh on Ubuntu and Debian systems. Some of the benefits of using ZSH over Bash include: Enhanced command completion: ZSH offers better command completion than Bash, including the ability to use tab completion for options and arguments. More powerful globbing: ZSH has a more powerful globbing (wildcard matching) system…

On Linux, you may want to find large files or directories that are taking up too much space. This guide will show you simple steps to search for these large files and directories using terminal commands. Using the du Command The du command (disk usage) is useful for checking the size of files and directories. Here’s how to use it: Open the Terminal: Open the terminal window on your Linux system. Search for Large Directories: To check which directories are taking up the most space, use the following command: du -h –max-depth=1 /path/to/directory Example: du -h –max-depth=1 /home/user This command…

Bash is one of the most popular shells and is used by many Linux users. One of the great things you can do with Bash is removed duplicate lines from files. It’s a great way to declutter a file and make it look cleaner and more organized. This can be done with a simple command in the Bash shell. All you have to do is type in the command “sort -u” followed by the name of the file. This will take the file and sort the content, then use the command “uniq” to remove all duplicates. It’s an easy and…

In FirewallD, the `–source` option allows you to specify a network or an IP address as the source for applying the rules. It is used to specify the network or IP address that is allowed to access the port or service that is being opened. The `–add-source` option is used to specify multiple networks or IP addresses as the source for the rules being applied. It is used in conjunction with the `–permanent` option to add multiple sources to a rule already configured in the firewall. Open Port for Single IP/Network For example, the following command will open port `80`…

In a high-traffic website, it’s essential to ensure that the web server can handle a large number of requests without causing server overload or poor performance. One way to achieve this is by using a reverse proxy server in front of the web server. A reverse proxy server, such as Nginx, can handle requests from clients and forward them to the web server, offloading some of the work and improving performance. In this article, we will discuss how to configure Nginx as a reverse proxy in front of Apache to optimize high-traffic websites. Step 1: Installing Nginx The first step…

Ubuntu is a popular open-source operating system based on the Linux kernel. It is widely used on personal computers, servers, and in cloud computing environments. One of the key tasks in managing a Ubuntu system is managing users and groups. In this article, we will explain how to add and delete users in Ubuntu 22.04. Before we begin, it is important to note that in Ubuntu, only users with administrative privileges (also known as “root” users) can add and delete other users. If you do not have administrative privileges, you will need to ask an administrator to perform these tasks…

To detect and handle errors in a bash script, you can use the `set -e` and `trap` commands, as well as the `if` and `case` statements and the `||` and `&&` operators. You can use the set -e command at the beginning of your script to enable this behavior, or you can use it before individual commands to enable it only for those commands. It’s important to note that the `set -e` command only affects the exit status of individual commands. It does not catch errors caused by syntax errors or other issues in the script itself. To catch these…

In Linux, PS1 is an environment variable that specifies the format of the command prompt displayed in the terminal. It stands for “Prompt String 1” and it is used to customize the appearance of the prompt. By default, the bash prompt includes the current username, hostname, and current working directory, followed by the `$` symbol for a regular user or the `#` symbol for the root user. The prompt is displayed on the command line, and it indicates that the terminal is ready for input. You can customize the bash prompt by modifying the value of the PS1 variable. For…

To copy a file to multiple directories in Linux, you can use the `cp` command with the `xargs` command. Here all the destination directories will be piped as standard input to the `xargs` command. and specify a list of directories separated by space. For example: echo dir1 dir2 dir3 | xargs -n 1 cp -v file.txt This will copy the file file.txt to the directories dir1, dir2, and dir3. Alternatively, you can use the for loop to copy the file to multiple directories. For example: for dir in dir1 dir2 dir3; do cp file.txt $dir done This will loop through…