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SLEEP(1) BSD General Commands Manual SLEEP(1)
sleep -- suspend execution for an interval of time
The sleep utility suspends execution for a minimum of seconds. It is usually used to sched-
ule the execution of other commands (see EXAMPLES below).
Note: The NetBSD sleep command will accept and honor a non-integer number of specified sec-
onds. 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 seconds left to sleep is
printed on the standard output.
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.
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 command_file. (See the
To reiteratively run a command (with csh(1)):
if (! -r zzz.rawdata) then
foreach i (*.rawdata)
awk -f collapse_data $i >> results
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 pro-
gram 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.
at(1), nanosleep(2), sleep(3)
The sleep command is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible.
BSD August 13, 2011 BSD
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