sudo tmutil listlocalsnapshots / | awk -F. '{ system("sudo tmutil deletelocalsnapshots " $4); }'
Where:
sudo tmutil listlocalsnapshots /
List of all local snapshots in form:
com.apple.TimeMachine.2017-11-27-142931
com.apple.TimeMachine.2017-11-27-152919
com.apple.TimeMachine.2017-11-27-163113
com.apple.TimeMachine.2017-11-27-173243
com.apple.TimeMachine.2017-11-27-183511
com.apple.TimeMachine.2017-11-27-193725
com.apple.TimeMachine.2017-11-27-203137
...
The command:
awk -F. { print $4; }
Will print date part.
And command:
sudo tmutil deletelocalsnapshots
will delete given date.
And don't forget to reboot after deleting.