sleep(1) - NetBSD Manual Pages

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SLEEP(1)                NetBSD General Commands Manual                SLEEP(1)


NAME
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.
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 a half hour before running the script com- mand_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 (*.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 ALSO
at(1), nanosleep(2), sleep(3)
STANDARDS
The sleep command is expected to be IEEE Std 1003.2 (``POSIX.2'') compat- ible. NetBSD 5.1 April 18, 1994 NetBSD 5.1
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