O programa 'sleep' é a parte do pacote coreutils.
Apenas execute este comando no console:
man sleep
E você encontrará a página de manual sobre este programa.
NAME
sleep - delay for a specified amount of time
SYNOPSIS
sleep NUMBER[SUFFIX]...
sleep OPTION
DESCRIPTION
Pause for NUMBER seconds. SUFFIX may be 's' for seconds (the default), 'm' for minutes, 'h' for hours or 'd' for days. Unlike most implementations that require NUMBER be an integer, here
NUMBER may be an arbitrary floating point number. Given two or more arguments, pause for the amount of time specified by the sum of their values.
--help display this help and exit
--version
output version information and exit
AUTHOR
Written by Jim Meyering and Paul Eggert.