Stack Pointer - Technology Deciphered

Unix / Linux: How to Create Zombie Process

September 17th, 2017

Explains how zombie processes or defunct processes are created on Unix / Linux. Also explains how the zombie process can be removed from the process table. A simple C program is used to demonstrate the creation of zombie processes.

Hello Stack Pointer, Goodbye Digital Internals

September 12th, 2017

Blog has been renamed from Digital Internals to Stack Pointer. Old urls will automatically redirect to the new urls.

Linux: Run Cron Job on Reboot

August 27th, 2017

Explains how to schedule a cron job to run after Linux / BSD system reboot or system startup using @reboot Vixie cron macro.

Linux: Get Ubuntu Distribution Codename

August 13th, 2017

Explains how to get the Ubuntu release codename such as trusty (14.04) and xenial (16.04) from the command line.

Linux: Allow SSH Root Login From Specific IP

June 11th, 2017

Explains how to allow ssh root logins only from certain hosts or IP addresses using Match block keyword in sshd_config.

Linux: Get Time in Timezone

May 21st, 2017

Explains how to get the current time in a different timezone on Linux without changing the system timezone.

Unix / Linux: Run Sudo Without Password

April 9th, 2017

Explains how to run sudo commands without a password on Unix and Linux systems by modifying the sudoers configuration file.

Linux: Pretty Print Mount Output

March 12th, 2017

Explains how to pretty print the output of the mount command on Linux by formatting the output using printf, awk and column commands.

Linux: SSH Session Logging

February 12th, 2017

Explains how to perform ssh session logging on Linux using tee and screen commands.

Linux: Make File Undeletable / Immutable

January 8th, 2017

Explains how to make a file undeletable or immutable on Linux using extended file attributes. Even a root user will not be able to delete a file with the immutable attribute set.