SLEEP(1)                FreeBSD General Commands Manual               SLEEP(1)

NAME
     sleep - suspend execution for an interval of time

SYNOPSIS
     sleep seconds

DESCRIPTION
     The sleep command suspends execution for a minimum of seconds.

     If the sleep command receives a signal, it takes the standard action.
     When the SIGINFO signal is received, the estimate of the amount of
     seconds left to sleep is printed on the standard output.

IMPLEMENTATION NOTES
     The SIGALRM signal is not handled specially by this implementation.

     The sleep command allows and honors a non-integer number of seconds to
     sleep in any form acceptable by strtod(3).  This is a non-portable
     extension, but is also implemented in GNU sh-utils since version 2.0a
     (released in 2002).

EXIT STATUS
     The sleep utility exits 0 on success, and >0 if an error occurs.

EXAMPLES
     To schedule the execution of a command for x number seconds later (with
     csh(1)):

           (sleep 1800; sh command_file >& errors)&

     This incantation would wait a half hour before running the script
     command_file.  (See the at(1) utility.)

     To reiteratively run a command (with the csh(1)):

           while (1)
                   if (! -r zzz.rawdata) then
                           sleep 300
                   else
                           foreach i (`ls *.rawdata`)
                                   sleep 70
                                   awk -f collapse_data $i >> results
                           end
                           break
                   endif
           end

     The scenario for a script such as this 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 the file
     zzz.rawdata, when the file is found, then another portion processing is
     done courteously by sleeping for 70 seconds in between each awk job.

SEE ALSO
     nanosleep(2), sleep(3)

STANDARDS
     The sleep command is expected to be IEEE Std 1003.2 ("POSIX.2")
     compatible.

HISTORY
     A sleep command appeared in Version 4 AT&T UNIX.

FreeBSD 13.1-RELEASE-p6        December 31, 2020       FreeBSD 13.1-RELEASE-p6