Nudge Region/Event Length Left by Division

Make the currently selected Region/Event shorter by the division value. Moves the end position of the event earlier in time.

The “Nudge Region/Event Length” commands are only mentioned in passing in the “View and edit music notation” section of the manual. Clearly the commands are useful in places other than simply notation.

I think I am more fascinated by the “slip” and “rotate” region commands.

Move regions in the Logic Pro Tracks area — Apple Support

You can nudge regions (move them in small increments) left or right using key commands. To nudge regions, you first set the nudge value, then move selected regions by this value. Alternatively, you can nudge regions by a set value.

  Apply Transform User Preset 30 to selected Events

The 30th of 30 — All the transform commands. Think of them as un-named macros or subroutines in a program.

Select MIDI events and apply the 30th preset to them…

Logic Pro MIDI Transform window overview — Apple Support

The MIDI Transform window is a powerful tool for edits that would otherwise be impossible (or tedious). For example, imagine an orchestral project that has been sent to you for editing. The individual violin and viola parts were recorded with a different string library. Two hundred MIDI regions contain aftertouch information that introduces an unpleasant pitch modulation, and some sample layer switching artifacts when played with your string samples. After looking at this aftertouch information, you discover that only a small range of values is causing the problem. Your options: edit your sampler instruments, manually remove all aftertouch information (region by region, or globally, thus losing the performance benefits that the aftertouch information provides), or alter the problematic values in the MIDI Transform window.

Logic Pro MIDI Transform presets overview — Apple Support

The table below describes the operations performed by the MIDI Transform window presets in Logic Pro.

  Toggle Auto Input Monitoring

Use this when doing punch recording. Typically you would have it on so you can hear previous recorded input that switches to “live” at the punch-in location.

You can use the key command to toggle the mode, configure the control bar to have the Auto-Input Monitoring button available (speaker with AUTO underneath), or toggle the setting with the Record button (control-click for menu).

Turn on input monitoring for audio tracks — Logic Pro X Help

You can turn on input monitoring to monitor audio tracks that are not enabled for recording. This is useful for setting audio levels or practicing parts before you commit to recording.

Punch in and out of audio recordings in Logic Pro — Apple Support

When it comes to judging punch-in and punch-out points during punch recording, you should turn on auto input monitoring (which it is, by default). This setting allows you to hear the input signal only during the actual recording; before and afterward you’ll hear the previously recorded audio on the track. If auto input monitoring is turned off, you can always hear the input signal.