How can I determine the size of a directory or folder in Linux?
du -hs /path/to/directory -h: human-readable -s: summary (don't show size of each individual file within the...
Tutorial: How to use Linux Screen
A problem that often arises when you’re dealing with lots of data is that it takes forever to process. So you SSH into your Amazon EC2 machine,...
How to password-protect a PDF file on Ubuntu
In a terminal, type: sudo apt-get install pdftk Then, to add a password to a PDF file, type: pdftk <input-file> output...
Can’t restart Apache in Ubuntu
When I try to restart Apache using the command: sudo apachectl -k restart I get this error: apache2: Could not reliably determine the server’s...