sleep - phpMan

File: coreutils.info,  Node: sleep invocation,  Up: Delaying
25.1 `sleep': Delay for a specified time
========================================
`sleep' pauses for an amount of time specified by the sum of the values
of the command line arguments.  Synopsis:
     sleep NUMBER[smhd]...
   Each argument is a number followed by an optional unit; the default
is seconds.  The units are:
`s'
     seconds
`m'
     minutes
`h'
     hours
`d'
     days
   Historical implementations of `sleep' have required that NUMBER be
an integer, and only accepted a single argument without a suffix.
However, GNU `sleep' accepts arbitrary floating point numbers (using a
period before any fractional digits).
   The only options are `--help' and `--version'.  *Note Common
options::.
   Due to shell aliases and built-in `sleep' command, using an
unadorned `sleep' interactively or in a script may get you different
functionality than that described here.  Invoke it via `env' (i.e.,
`env sleep ...') to avoid interference from the shell.
   An exit status of zero indicates success, and a nonzero value
indicates failure.