How to delete old Time Machine backup with tmutil command. (then start and show backup status)

# How to delete old Time Machine backup with tmutil command.

## Objective:

* just my memorandum :)

## System:

### My Time Machine:

* Ubuntu 14.04 trusty
    * netatalk 2.2.2

* netatalk configuration

```shell-session
# cat /etc/netatalk/AppleVolumes.default | grep "TimeMachine-for-mba1"
/mnt/export/TimeMachine4  "TimeMachine-for-mba1"      options:usedots,upriv,tm ea:ad allow:hirofumi volsizelimit:250000
```

### Client:

* Mac OS X 10.11.3 (El Capitan)

```shell-session
# tmutil destinationinfo
====================================================
Name          : TimeMachine-for-mba1
Kind          : Network
URL           : afp://hirofumi@fs1._afpovertcp._tcp.local./TimeMachine-for-mba1
Mount Point   : /Volumes/TimeMachine-for-mba1
ID            : 41302FE3-081D-4034-8B81-F7C0FD3A0C3C
```

## list backups:

```shell-session
tmutil listbackups
```
```shell-session:sample
# tmutil listbackups
/Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-03-31-001335
/Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-04-01-005550
/Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-04-02-003630
(snip)
```

## delete backup(s):

```shell-session
tmutil delete <backup_target>
```
```shell-session:sample_for_delete_oldest
# tmutil delete "`tmutil listbackups | head -1`"
Deleting: /Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-03-31-001335
Deleted (5.3G): /Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-03-31-001335
Total deleted: 5.3G
```
```shell-session:sample_for_delete_old_3
# for ((x=1; x<=3; x++)) ; do tmutil delete "`tmutil listbackups | head -1`" ; done
Deleting: /Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-04-01-005550
Deleted (1.9G): /Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-04-01-005550
Total deleted: 1.9G
Deleting: /Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-04-02-003630
Deleted (2.0G): /Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-04-02-003630
Total deleted: 2.0G
Deleting: /Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-04-03-010626
Deleted (7.6G): /Volumes/Time Machine Backups/Backups.backupdb/Hirofumi’s MacBook Air/2016-04-03-010626
Total deleted: 7.6G
```

## start backup:

```shell-session
tmutil startbackup
```

## show backup state:

ref. http://apple.stackexchange.com/questions/162464/time-machine-progress-from-the-command-line

```shell-session
tmutil status
```
```shell-session:sample1
# tmutil status
Backup session status:
{
    BackupPhase = Copying;
    ClientID = "com.apple.backupd";
    DateOfStateChange = "2016-04-11 12:07:18 +0000";
    DestinationID = "41302FE3-081D-4034-8B81-F7C0FD3A0C3C";
    DestinationMountPoint = "/Volumes/Time Machine Backups";
    Percent = "0.04944647446240578";
    Progress =     {
        TimeRemaining = 3823;
        "_raw_totalBytes" = 4347141887;
        bytes = 238834267;
        files = 9550;
        totalBytes = 4781856075;
        totalFiles = 9550;
    };
    Running = 1;
    Stopping = 0;
    "_raw_Percent" = "0.05494052718045087";
}
```
```shell-session:sample2
# tmutil status | awk '/_raw_Percent/ {print $3}' | grep -o '[0-9].[0-9]\+' | awk '{print $1*100,"% backed up"}'
17.8677 % backed up
```