Delay for a specified time, pause for an amount of time specified by the sum of the values of the command line arguments.
Syntax sleep [NUMBER [smhd]]... Key: s : seconds (default) m : minutes h : hours d : days
An alternative to sleep is setting the variable TMOUT, setting TMOUT=1200 will exit the shell if nothing is typed for 20 minutes. This can be a useful security fallback to ensure you don't remain logged on to a production server for too long.
“O sleep, O gentle sleep, nature's soft nurse, how have I frighted thee, that thou no more wilt weigh my eyelids down, and steep my senses in forgetfulness” ~ Shakespeare (Henry IV)
nice - Change job scheduling priority.
Equivalent Windows commands: SLEEP - Wait for x seconds.