I have a long running script at the remote computer.
I don't want terminate my ssh session, and need enter it into a shell script.
How is it possible to prevent my Mac from falling into sleep from the command line?
In Mountain Lion you can use the
caffeinate -u -t 1000
will prevent idle sleep for 1000 seconds.
The solution to this problem is not keeping the client (your Mac) awake. Using approaches like this are undependable. What happens if the network connection is lost? Even if your Mac is awake, the script will halt.
If your long-running script is called
eternity.sh, try the following:
nohup /path/to/eternity.sh > /path/to/output.out &
Now you can even close the connection and your script will keep running. The
& backgrounds the process so you can keep the connection open and enter commands. View any output from your script via:
tail -f /path/to/output.out
The paths in the examples are optional if the script is on your path and you want script output to be written to
output.out in the current directory.
I manage scripts that run for days at a time. Scripts like these should be detached from the terminal. Thankfully,
nohup provides an easy-to-remember command invocation to achieve this--think no hangup.
Another option is pmset. Use the command
pmset noidle to prevent sleep as long as
pmset is running. Unfortunately, it requires a separate Terminal window with
pmset running in it. However, the other option,
caffeinate, only lets you set a certain time. So it's a matter of choosing whether you want to open a second SSH session, or deal with a time restraint.
Edit: According to binarybob's comment, you can actually run it in the background like this:
pmset noidle & To get back to
caffeinate -i -s /bin/ssh ...
-i - Prevent idle sleep.
-s - Prevent system sleep (entirely, even if you close the lid). Note: it only works while on AC power.
/bin/ssh - Just keep writing the command you want to execute. Using
ssh directly instead of
/bin/ssh should also work.
Results: Your system will not sleep as long as the
ssh command is running.
If you are looking for the nuclear option like I was:
sudo systemsetup -setcomputersleep Never
I find that for macOS 13, Ventura,
sudo pmset sleep 0 will change the Settings > Displays > Advanced > Energy > Prevent automatic sleeping when the display is off, to enabled.
Similarly, setting it to anything other than
0 will disable that setting (and presumably change some value elsewhere).
You have to exit and restart settings to observe the change - it doesn't update as soon as the pmset command has run.
the installed policies on my machine make everything dependent on the display, so the only thing that worked for me was to invoke
caffeinate with the
$ caffeinate -d
excerpt from the man page:
caffeinate – prevent the system from sleeping on behalf of a utility
caffeinate [-disu] [-t timeout] [-w pid] [utility arguments...]
caffeinate creates assertions to alter system sleep behavior. If no assertion flags are specified, caffeinate creates an assertion to prevent idle sleep. If a utility is specified, caffeinate creates the assertions on the utility's behalf, and those assertions will persist for the duration of the utility's execution. Otherwise, caffeinate creates the assertions directly, and those assertions will persist until caffeinate exits.
-d Create an assertion to prevent the display from sleeping.