Arbitrary precision calculator.
Clear the screen.
Get command information from the GNU hypertext reader.
Get information on a command.
Reduce a job’s priority.
Launch a command that will continue to run after logging out.
Run a program on the next available virtual terminal.
Set your login password.
Produce a transcript of your login session.
Become a different user, often the superuser.
Execute an authorized command as root or another user.
Simultaneously store output in file and send to screen.
Time the execution of a command.
Send a message to all terminals.
Print the current user id.
Process many arguments in manageable portions.