Sleep

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Sleep random seconds in programming

MS-DOS[edit]

Approach 1: %RANDOM% + ping local[edit]

batch file - .bat random timeout - Stack Overflow

  • %RANDOM% returns an integer between 0 and 32767.
  • 60 is the range of values you want: 0 to 60.
  • 32768 is the range of values returned by %RANDOM% (0 to 32767).
  • 5 is the minimum value you want. The original range of values you want '0 to 60' became '5 ~ 65'.
  • ping local address: /n <Count> "Specifies the number of echo Request messages sent. The default is 4."[1][2]

BAT file:

REM print current date & time
ECHO %date% %time%

REM sleep 5 ~ 65 seconds
SET /a timeout=%RANDOM% * 60 / 32768 + 5
ping 127.0.0.1 -n %timeout% > nul

REM print current date & time
ECHO %date% %time%

Approach 2: sleep package of CygWin[edit]

Requirement: Install Cygwin on Win Os windows.png & install sleep package (How-to: Setting Up Cygwin/X)

Verify the installation of sleep package[3][4]

  1. Key-in cmd to open command prompt (How to Open Command Prompt (Windows 10, 8, 7, Vista, XP))
  2. Key-in one of following commands
    • Key-in where sleep if you add installation path of CygWin to system path (How to setup my system path). Or
    • Key-in dir C:\cygwin64\bin\sleep.exe if the installation path of CygWin is C:\cygwin64\.
C:\Users\user>dir C:\cygwin64\bin\sleep.exe

# successful condition
C:\cygwin64\bin\sleep.exe

# failed condition
File Not Found

BAT file:

REM print current date & time
ECHO %date% %time%

REM sleep 5 ~ 65 seconds
SET /a timeout=%RANDOM% * 60 / 32768 + 5
C:\cygwin64\bin\sleep.exe %timeout%

REM print current date & time
ECHO %date% %time%

Approach 3: TIMEOUT[edit]

Alternative command: Icon exclaim.gif The following command ECHO %date% %time% will not be executed after TIMEOUT %timeout% was executed.

BAT file:

SET /a timeout=%RANDOM% * 60 / 32768 + 5
TIMEOUT %timeout%

ECHO %date% %time%

BASH[edit]

Approach1: sleep[edit]

Tested on Linux Os linux.png & Mac Os mac.png [5]

# print current date & time
echo $(date '+%Y-%m-%d %H:%M:%S')

# sleep 5 ~ 65 seconds
timeout=$(($RANDOM * 60 / 32768 + 5))
sleep $timeout

# print current date & time
echo $(date '+%Y-%m-%d %H:%M:%S')

Approach2: ping[edit]

Tested on Linux Os linux.png & Mac Os mac.png

ping local address: -c <Count> "Stop after sending (and receiving) count ECHO_RESPONSE packets."[6]

# print current date & time
echo $(date '+%Y-%m-%d %H:%M:%S')

# sleep 5 ~ 65 seconds
timeout=$(($RANDOM * 60 / 32768 + 5))
ping 127.0.0.1 -c $timeout > nul

# print current date & time
echo $(date '+%Y-%m-%d %H:%M:%S')

Approach3: usleep[edit]

usleep(3) - Linux man page "suspend execution for microsecond intervals" (1 second = 1 000 000 microsecond). Tested on Linux Os linux.png

# print current date, time & nanoseconds
echo $(date '+%Y-%m-%d %H:%M:%S')$(date '+.%N')

# sleep 0.2 ~ 1.2 seconds
timeout=$(($RANDOM * 1000000 / 32768 + 200000))
echo $timeout
usleep $timeout

# print current date, time & nanoseconds
echo $(date '+%Y-%m-%d %H:%M:%S')$(date '+.%N')

PHP[edit]

JavaScript[edit]

References[edit]

Related[edit]