sleep - Suspends execution for at least the specified time
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Non-negative integer specifying the number of seconds for
which execution is to be suspended.
The sleep command suspends execution of a process for at
least the interval specified by seconds, which can range
from 0 to 2,147,483,647 seconds. Depending on system
activity, the actual time of suspension may be longer.
See the sleep(3) reference page.
[Tru64 UNIX] seconds can be entered as a non-negative
decimal, octal, or hexadecimal value.
If sleep receives a SIGALARM signal before process execution
has resumed, sleep takes one of the following
actions: Terminates normally with a 0 (zero) exit status.
(See the sleep(3) reference page for more information.)
Ignores the signal Performs default processing
The following exit values are returned: Execution was successfully
suspended for at least the requested time, or a
SIGALARM signal was received. An error occurred.
To display a message at 4-minute intervals for 20 minutes,
create a shell script called remind containing the following:
for i do sleep 240; echo $i sleep 240; echo $i
sleep 240; echo $i sleep 240; echo $i sleep 240;
echo $i done
To display the message Try calling NHK at 4-minute
intervals, enter: remind 'Try calling NHK' To run a
command at regular intervals, create a shell script
containing the following:
while true do
sleep 60 done
This displays the date and time once a minute. To
execute a command after a specified interval, enter
the following; (sleep 3600; echo Time\'s up) &
This displays the message "Time's up" after one
ENVIRONMENT VARIABLES [Toc] [Back]
The following environment variables affect the execution
of sleep: Provides a default value for the internationalization
variables that are unset or null. If LANG is unset
or null, the corresponding value from the default locale
is used. If any of the internationalization variables
contain an invalid setting, the utility behaves as if none
of the variables had been defined. If set to a non-empty
string value, overrides the values of all the other internationalization
variables. Determines the locale for the
interpretation of sequences of bytes of text data as characters
(for example, single-byte as opposed to multibyte
characters in arguments). Determines the locale for the
format and contents of diagnostic messages written to
standard error. Determines the location of message catalogues
for the processing of LC_MESSAGES.
Functions: alarm(3), pause(3), sigaction(2), sleep(3)
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