Added Time Machine guide

how-to-use-time-machine-and-apfs-snapshots-on-macos/README.md

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+<!--
+Title: How to use Time Machine and APFS snapshots on macOS
+Description: Learn how to use Time Machine and APFS snapshots on macOS.
+Author: Sun Knudsen <https://github.com/sunknudsen>
+Contributors: Sun Knudsen <https://github.com/sunknudsen>
+Reviewers:
+Publication date: 2021-04-02T17:40:53.608Z
+Listed: true
+-->
+
+# How to use Time Machine and APFS snapshots on macOS
+
+## Time Machine setup guide
+
+### Step 1: exclude folders from Time Machine
+
+> Heads-up: excluded folders vary depending on use case.
+
+![Format Time Machine drive](./exclude.png?shadow=1)
+
+### Step 2: format Time Machine disk as “Mac OS Extended (Journaled, Encrypted)” using “Disk Utility”
+
+> WARNING: DATA ON TIME MACHINE DISK WILL BE PERMANENTLY DELETED.
+
+![Format Time Machine drive](./format.png?shadow=1)
+
+### Step 3: enable “Encrypt Backup Disk” and click “Use as Backup Disk”
+
+![Format Time Machine drive](./enable-time-machine.png?shadow=1&width=568)
+
+### Step 4: confirm encryption is enabled and enable “Show Time Machine in menu bar”
+
+![Format Time Machine drive](./confirm-encryption.png?shadow=1)
+
+Encrypted
+
+👍
+
+## Time Machine usage guide
+
+### Create backup
+
+Click “Time Machine” menu bar icon and then “Back Up Now” or run `tmutil startbackup`.
+
+### Delete specific backup
+
+Heads-up: use `tmutil listbackups` to list backups.
+
+```shell
+sudo tmutil delete "/Volumes/LaCie/Backups.backupdb/Sun’s MacBook Pro/2021-04-05-082332"
+```
+
+## APFS snapshot usage guide
+
+### Create local APFS snapshot
+
+```shell
+tmutil localsnapshot
+```
+
+### List local APFS snapshots
+
+```shell
+tmutil listlocalsnapshots /
+```
+
+### Mount local read-only APFS snapshot
+
+Heads-up: use `umount /tmp/snapshot` to unmount snapshot.
+
+Replace `com.apple.TimeMachine.2021-04-05-082935.local` with snapshot from [List local APFS snapshots](#list-local-apfs-snapshots).
+
+```shell
+mkdir -p /tmp/snapshot
+mount_apfs -s com.apple.TimeMachine.2021-04-05-082935.local / /tmp/snapshot
+open /tmp/snapshot
+```
+
+### Restore local APFS snapshot
+
+Restart computer and press `cmd+r` to boot to recovery mode.
+
+Select “Restore From Time Machine Backup”, then “Macintosh HD”, choose local snapshot, click “Continue” and “Continue” again to confirm.
+
+### Delete specific local APFS snapshot
+
+> Heads-up: use `tmutil listlocalsnapshotdates` to list local snapshot dates.
+
+```
+tmutil deletelocalsnapshots 2021-04-05-082935
+```
+
+### Delete all local APFS snapshot
+
+```
+tmutil deletelocalsnapshots /
+```