HowTo: Revoke OpenSSH Keys and Disable User Access

in Categories last updated November 6, 2012

Many users are using ssh to log into a remote machine and append the indicated identity file to machine’s ~/.ssh/authorized_keys file. I recently moved one of my server, and I would like to revoke openssh keys and disable user access under Linux operating systems. How do I revoke OpenSSH keys under Unix or Linux operating systems?

Linux / Unix: sed Command Print Only Matching Lines

in Categories last updated October 19, 2012

I see many examples and man pages on how to do operations like search-and-replace using sed. But, I want to match a given string or a regular pattern expression and display on the screen. How do I print lines with matching pattern using sed command only under Unix like operating systems?

Linux: warning: CUPSEXT could not be loaded. Please check HPLIP installation.

in Categories , last updated September 29, 2012

I‘m trying to install latest version of Hewlett-Packard’s Linux Imaging and Printing software (HPLIP) for my office jet printer. In order to install latest version of HPLIP I removed the hplip-gui, hplip, hplip-cups, hplip-data, hpijs, and hpijs-ppds Debian Linux packages However, I’m getting the following error:

Debian warning: CUPSEXT could not be loaded. Please check HPLIP installation.

How do I fix this error while installing hplip-3.12.9.run under Debian Linux 6.0.5 amd64 bit?