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sleep(1) [netbsd man page]

SLEEP(1)						    BSD General Commands Manual 						  SLEEP(1)

sleep -- suspend execution for an interval of time SYNOPSIS
sleep 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 seconds 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 command_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 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
at(1), nanosleep(2), sleep(3) STANDARDS
The sleep command is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible. BSD
August 13, 2011 BSD

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sleep(3UCB)					     SunOS/BSD Compatibility Library Functions					       sleep(3UCB)

sleep - suspend execution for interval SYNOPSIS
/usr/ucb/cc [ flag ... ] file ... int sleep( seconds); unsigned seconds; DESCRIPTION
sleep() suspends the current process from execution for the number of seconds specified by the argument. The actual suspension time may be up to 1 second less than that requested, because scheduled wakeups occur at fixed 1-second intervals, and may be an arbitrary amount longer because of other activity in the system. sleep() is implemented by setting an interval timer and pausing until it expires. The previous state of this timer is saved and restored. If the sleep time exceeds the time to the expiration of the previous value of the timer, the process sleeps only until the timer would have expired, and the signal which occurs with the expiration of the timer is sent one second later. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |MT-Level |Async-Signal-Safe | +-----------------------------+-----------------------------+ SEE ALSO
alarm(2), getitimer(2), longjmp(3C), siglongjmp(3C), sleep(3C), usleep(3C), attributes(5) NOTES
Use of these interfaces should be restricted to only applications written on BSD platforms. Use of these interfaces with any of the system libraries or in multi-thread applications is unsupported. SIGALRM should not be blocked or ignored during a call to sleep(). Only a prior call to alarm(2) should generate SIGALRM for the calling process during a call to sleep(). A signal-catching function should not interrupt a call to sleep() to call siglongjmp(3C) or longjmp(3C) to restore an environment saved prior to the sleep() call. WARNINGS
sleep() is slightly incompatible with alarm(2). Programs that do not execute for at least one second of clock time between successive calls to sleep() indefinitely delay the alarm signal. Use sleep(3C). Each sleep(3C) call postpones the alarm signal that would have been sent during the requested sleep period to occur one second later. SunOS 5.10 12 Feb 1993 sleep(3UCB)
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