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SLEEP(1) BSD General Commands Manual SLEEP(1)
sleep -- suspend execution for an interval of time
The sleep command suspends execution for a minimum of seconds.
If the sleep command receives a signal, it takes the standard action.
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.
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
To reiteratively run a command (with the csh(1)):
if (! -r zzz.rawdata) then
foreach i (`ls *.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.
The sleep utility exits 0 on success, and >0 if an error occurs.
The sleep command is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible.
A sleep command appeared in Version 4 AT&T UNIX.
BSD April 18, 1994 BSD
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