SLEEP(1) BSD General Commands Manual SLEEP(1)NAMEsleep — suspend execution for an interval of time
SYNOPSISsleep seconds
DESCRIPTION
The sleep utility suspends execution for a minimum of seconds. It is
usually used to schedule the execution of other commands (see EXAMPLES
below).
Note: The NetBSD sleep command will accept and honor a non-integer number
of specified seconds. This is a non-portable extension, and its use will
nearly guarantee that a shell script will not execute properly on another
system.
When the SIGINFO signal is received, the estimate of the amount of sec‐
onds left to sleep is printed on the standard output.
EXIT STATUS
The sleep utility exits with one of the following values:
0 On successful completion, or if the signal SIGALRM was received.
>0 An error occurred.
EXAMPLES
To schedule the execution of a command for 1800 seconds later:
(sleep 1800; sh command_file >& errors)&
This incantation would wait half an hour before running the script com‐
mand_file. (See the at(1) utility.)
To reiteratively run a command (with csh(1)):
while (1)
if (! -r zzz.rawdata) then
sleep 300
else
foreach i (*.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 run‐
ning 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 cre‐
ated). The script checks every five minutes for the file zzz.rawdata,
when the file is found, then another portion processing is done courte‐
ously by sleeping for 70 seconds in between each awk job.
SEE ALSOat(1), nanosleep(2), sleep(3)STANDARDS
The sleep command is expected to be IEEE Std 1003.2 (“POSIX.2”) compati‐
ble.
BSD August 13, 2011 BSD
