Sleep: Difference between revisions
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This page was last edited on 12 July 2021, at 23:09.
Created page with "<br /> == Sleep to the nearest minute or hour == This can be done with some bash arithmetic and applying modulus to 60 seconds for 1 minute or 3600 seconds for 1 hour. {{High..." |
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== Sleep to the nearest minute or hour == | ==Sleep to the nearest minute or hour== | ||
This can be done with some bash arithmetic and applying modulus to 60 seconds for 1 minute or 3600 seconds for 1 hour. | This can be done with some bash arithmetic and applying modulus to 60 seconds for 1 minute or 3600 seconds for 1 hour. | ||
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=== With millisecond precision === | ===With millisecond precision=== | ||
If you need to synchronize a task by the millisecond, you can use <code>date +%s%N</code> which will print the timestamp with nanoseconds. Divide by 1000 for milliseconds and apply the same logic as above. | If you need to synchronize a task by the millisecond, you can use <code>date +%s%N</code> which will print the timestamp with nanoseconds. Divide by 1000 for milliseconds and apply the same logic as above.{{Highlight | ||
| code = # Next minute | |||
usleep $((60000 - (`date +%s%N` / 1000) % 60000 )) | |||
# Next hour | |||
usleep $((3600000 - (`date +%s%N` / 1000) % 3600000 )) | |||
| lang = bash | |||
}}Synchronizing bash scripts with this method works quite well as long as all the machines are using the same NTP server. I was able to precisely synchronize an audio file playing across an entire computer lab of over 100 machines through the PC speaker. | |||
Revision as of 23:09, 12 July 2021
Sleep to the nearest minute or hour
This can be done with some bash arithmetic and applying modulus to 60 seconds for 1 minute or 3600 seconds for 1 hour.
# Next minute
sleep $((60 - `date +%s` % 60))
# Next hour
sleep $((3600 - `date +%s` % 3600))
With millisecond precision
If you need to synchronize a task by the millisecond, you can use date +%s%N which will print the timestamp with nanoseconds. Divide by 1000 for milliseconds and apply the same logic as above.
# Next minute
usleep $((60000 - (`date +%s%N` / 1000) % 60000 ))
# Next hour
usleep $((3600000 - (`date +%s%N` / 1000) % 3600000 ))
Synchronizing bash scripts with this method works quite well as long as all the machines are using the same NTP server. I was able to precisely synchronize an audio file playing across an entire computer lab of over 100 machines through the PC speaker.