In the TCSH (also known as the C shell), you can check whether a directory is empty or not using the ls command and the test command. Here’s how: if ( ! (`ls -A $dir 2>/dev/null`) ) then echo “$dir is empty” else echo “$dir is not empty” endif In this example, the ls command … Read more

To save a file in Unix using the command line, you can use the vi editor. Here’s how: Open the vi editor: $ vi filename Replace filename with the name of the file you want to create. Press the i key to enter insert mode. Type or paste the content of the file. Press the … Read more

The “413 – Request Entity Too Large” error in Nginx occurs when a client tries to upload a file that is too large for Nginx to handle. This error can be solved by increasing the client_max_body_size directive in the Nginx configuration file. Here’s how: Open the Nginx configuration file: $ sudo nano /etc/nginx/nginx.conf Find the … Read more

You can remotely shut down a Linux or Unix computer from a Microsoft Windows computer using the ssh protocol and the shutdown command. Here’s how: Download and install an ssh client for Windows, such as PuTTY. Open the PuTTY client. In the Host Name (or IP address) field, enter the hostname or IP address of … Read more

To skip the first two fields and print the rest of the line using awk or cut, you can use the following command: With awk: $ awk ‘{$1=$2=””; print $0}’ input_file With cut: $ cut -d’ ‘ -f3- input_file Replace input_file with the name of your input file. The awk and cut commands will read … Read more

In Nginx, you can use the return directive to redirect a URL with the HTTP/1.1 301 Moved Permanently header. Here’s how: Open the Nginx configuration file: $ sudo nano /etc/nginx/nginx.conf Add the following code to the server block for the domain you want to redirect: server { listen 80; server_name <old_domain>; return 301 $scheme://<new_domain>$request_uri; } … Read more

To install the Firefox web browser on OpenBSD, you can use the pkg_add command. Here’s how: Open a terminal window. Update the package list: $ sudo pkg_add -u Install Firefox: $ sudo pkg_add firefox This will download and install the latest version of the Firefox web browser. Start Firefox: $ firefox & This will start … Read more

To download a password-protected large ISO image in Linux, you’ll need to provide the authentication credentials (username and password) to the server. The following is a general guideline for downloading a password-protected ISO image: Open a terminal window. Use the wget command to download the ISO image: $ wget –user=<username> –password=<password> <URL_of_the_ISO_image> Replace <username> and … Read more

The error message -bash: sudo: command not found means that the sudo command is not installed or not in your shell’s PATH. sudo is a command that allows users to run commands with elevated privileges (as the superuser). Here are some steps to resolve the error: Check if sudo is installed: $ which sudo If … Read more

To delete or remove the Master Boot Record (MBR) in Linux, you can use the dd command. The dd command can be used to overwrite the MBR with zeros or other data. Here’s how you can use dd to delete the MBR: Determine the device name of the disk you want to delete the MBR … Read more