Other Commands

Change the system default editor on Ubuntu (yes, I prefer vi over nano):
sudo update-alternatives --config editor

Repair all tables in all mysql databases on a server::
mysqlcheck -u root -p --auto-repair --check --optimize --all-databases

Create a self-signed SSL certificate
openssl req -new -newkey rsa:2048 -days 365 -nodes -x509 -keyout www.example.com.key -out www.example.com.crt

Create a new CSR
openssl req -out CSR.csr -new -newkey rsa:2048 -nodes -keyout privateKey.key

Burn a CD from the command line:
wodim -v -eject cdimage.iso

Rename multiple files with mmv:
mmv “*.jpeg” “#1.jpg”