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sleep(1) General Commands Manual sleep(1) NAME sleep - Suspends execution for at least the specified time SYNOPSIS sleep seconds STANDARDS Interfaces documented on this reference page conform to industry stan- dards as follows: sleep: XPG4, XPG4-UNIX Refer to the standards(5) reference page for more information about in- dustry standards and associated tags. OPTIONS None OPERANDS Non-negative integer specifying the number of seconds for which execu- tion is to be suspended. DESCRIPTION The sleep command suspends execution of a process for at least the in- terval 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. [DIGITAL] seconds can be entered as a non-negative decimal, octal, or hexadecimal value. NOTES If sleep receives a SIGALARM signal before process execution has re- sumed, 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 EXIT STATUS The following exit values are returned: Execution was successfully sus- pended for at least the requested time, or a SIGALARM signal was re- ceived. An error occurred. EXAMPLES 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 in- tervals, create a shell script containing the following: while true do date 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 hour. ENVIRONMENT VARIABLES The following environment variables affect the execution of sleep: Pro- vides 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 vari- ables contain an invalid setting, the utility behaves as if none of the variables had been defined. If set to a non-empty string value, over- rides the values of all the other internationalization variables. De- termines the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi- byte characters in arguments). Determines the locale for the format and contents of diagnostic messages written to standard error. Deter- mines the location of message catalogues for the processing of LC_MES- SAGES. SEE ALSO Commands: wait(1) Functions: alarm(3), pause(3), sigaction(2), sleep(3) Standards: standards(5) sleep(1)