The “warning: CUPSEXT could not be loaded. Please check HPLIP installation” message usually indicates that there is an issue with the HPLIP (HP Linux Imaging and Printing) package installed on your Linux system. This message can occur when trying to use the HPLIP toolbox or run a HP printer setup. To resolve this issue, you … Read more

You can blacklist a package from being installed in Debian or Ubuntu using the apt-mark command. This allows you to prevent a package from being installed, updated, or removed, even if it is specified as a dependency by another package. Here’s how to blacklist a package:   sudo apt-mark hold <package_name> Replace <package_name> with the … Read more

To find out the DNS server IP addresses or names in a Unix-like operating system, you can use the nslookup command or the cat command to view the /etc/resolv.conf file. Here’s how to use nslookup:   nslookup google.com This will return the IP address of the DNS server used by the system to resolve domain … Read more

The maximum length of arguments in a shell command is dependent on the underlying operating system and the system’s configuration. In most cases, the maximum length of arguments in a shell command is determined by the operating system’s shell and the maximum size of a command line buffer. In most Unix-like systems, the maximum length … Read more

To run the fsck utility to check and repair a Linux file system on a Synology NAS, you need to have access to the command line interface of the device. You can do this by using the ssh command to log into the NAS from a remote computer, or by using the built-in Terminal or … Read more

To change the hostname in CentOS 5/6, you can follow these steps: Open the /etc/sysconfig/network file in a text editor:   sudo nano /etc/sysconfig/network Change the HOSTNAME value to the desired hostname:   HOSTNAME=new_hostname Save the file and close the editor. Restart the network service to apply the changes:   sudo /etc/init.d/network restart Verify that … Read more

To set the PATH environment variable in the TCSH/CSH shell, you can use the following syntax:   set path = (dir1 dir2 dir3 …) Replace dir1, dir2, dir3, etc., with the directories you want to include in the PATH. For example, to add the /usr/local/bin directory to the PATH, you can use the following command: … Read more

To create a file in Unix, you can use the touch command. The touch command allows you to create an empty file with a specified name. Here’s the basic syntax:   touch file_name Replace file_name with the desired name for the new file. For example, to create a file named example.txt, you can use the … Read more

You can use the following command to list all environment variables in Linux:   printenv This will display a list of all the environment variables and their values. To view a specific environment variable, you can use the following syntax:   echo $VARIABLE_NAME Replace VARIABLE_NAME with the name of the environment variable you want to … Read more

To install Keychain on Ubuntu/Debian Linux, you can follow these steps: Update the package list:   sudo apt-get update Install Keychain:   sudo apt-get install keychain Add the following lines to your shell profile file (e.g., ~/.bashrc, ~/.bash_profile, or ~/.zshrc) to set up Keychain:   # Keychain eval “$(keychain –eval –agents ssh id_rsa)” Restart your … Read more