SLEEP(1) MidnightBSD General Commands Manual SLEEP(1)

NAME

sleep — suspend execution for an interval of time

SYNOPSIS

sleep seconds

DESCRIPTION

The sleep command suspends execution for a minimum of seconds.

If the sleep command receives a signal, it takes the standard action.

IMPLEMENTATION NOTES

The SIGALRM signal is not handled specially by this implementation.

The sleep command will accept and honor a non-integer number of specified seconds (with a ‘.’ character as a decimal point). 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 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 done courteously by sleeping for 70 seconds in between each awk job.

SEE ALSO

nanosleep(2), sleep(3)

STANDARDS

The sleep command is expected to be IEEE Std 1003.2 (‘‘POSIX.2’’) compatible.

HISTORY

A sleep command appeared in Version 4 AT&T UNIX.

MidnightBSD 0.3 April 18, 1994 MidnightBSD 0.3