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SLEEP(1) FreeBSD General Commands Manual SLEEP(1)
NAME
sleep - suspend execution for an interval of time
SYNOPSIS
sleep number[unit] ...
DESCRIPTION
The sleep command suspends execution for a minimum of number seconds (the
default, or unit s), minutes (unit m), hours (unit h), or days (unit d).
If multiple arguments are passed, the delay will be the sum of all
values.
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 supports other time units than seconds, honors a non-
integer number of time units to sleep in any form acceptable by
strtod(3), and accepts more than one delay value. These are non-portable
extensions, but they have also been 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
compatible.
HISTORY
A sleep command appeared in Version 4 AT&T UNIX.
FreeBSD 14.0-RELEASE-p11 May 25, 2022 FreeBSD 14.0-RELEASE-p11