SLEEP(1)

NAME
sleep - suspend execution for an interval of time

SYNOPSIS
sleep seconds

DESCRIPTION
The sleep utility suspends execution for a minimum of the specified number of seconds. This number must be positive and may contain a decimal fraction. sleep is commonly used to schedule the execution of other commands (see below).

ASYNCHRONOUS EVENTS

SIGALRM
    Terminate normally, with a zero exit status.

EXIT STATUS

EXAMPLES
Wait a half hour before running the script command_file (see also the at(1) utility):

    (sleep 1800; sh command_file >& errors)&

To repetitively run a command (with csh(1)):

    while (! -r zzz.rawdata)
    	sleep 300
    end
    foreach i (*.rawdata)
    	sleep 70
    	awk -f collapse_data $i >> results
    end

The scenario for such a script might be: a program currently running is taking longer than expected to process a series of files, and it would be nice to have another program start processing the files created by the first program as soon as it is finished (when zzz.rawdata is created). The script checks every five minutes for this file. When it is found, processing is done in several steps by sleeping 70 seconds between each awk(1) job.

To monitor the growth of a file without consuming too many resources:

    while true; do
    	ls -l file
    	sleep 5
    done

SEE ALSO
at(1)

STANDARDS
The sleep utility is compliant with the p1003.1-2008 specification.

The handling of fractional arguments is provided as an extension to that specification.

HISTORY
A sleep utility appeared in AT&T UNIX.