Stripping comments out of a configuration file can be useful when submitting it to a forum for others to study. This is how to do this.
ubuntu /etc/ssh $ grep -vE '^#' sshd_config
This will print the file to the terminal, allowing the user to copy the text with all comments stripped out. Very useful trick.
How to add a default route to a DNS server manually in Linux. (Source)
[email protected]:~$ sudo ip route add 0/0 via 172.29.59.1 dev wlan0
How to use the Linux cat command to read the contents of a folder. This is a cool trick.
Removing and creating files on UNIX/Linux and using the shred command.
Some very useful Linux commands.