ASR’s hidden documentation

As part of trying to trace down a separate mystery, the folks in the ##osx-server IRC room made an interesting discovery: Apple’s asr tool has hidden documentation.

Normally, to access Apple’s documentation on a command-line tool, you would use man toolname_here or toolname_here help. asr has both of those, but it also has a separate command that reveals additional asr options not mentioned in the regular man or help pages.

With asr help, you get the following output:

Usage: asr  
   is one of the following:
    asr help | version
    asr restore --source  --target  []
    asr restore --source asr:/// --file  []
    asr server  --source  --config  []
    asr imagescan --source  [--filechecksum] [--nostream] [--SHA1]
   is in bytes but may end with a scale factor (b, k, m, g)

common  are any of:
      --source  path or url to disk image file, mountpoint, or
                        web accessible disk image
      --puppetstrings   print out messages in format good for machine parsing
      --verbose         display verbose output
      --debug           display debug output

restore  are any of:
      --target  path to volume or mountpoint
      --erase           formats target volume
      --format  target format when erasing (defaults to source)
      --noprompt        don't require confirmation on erase
      --noverify        don't checksum results
      --buffers    number of buffers to use in block copy
      --buffersize   size of buffers to use in block copy
      --csumbuffers   number of buffers for the checksum if different
      --csumbuffersize  size of buffers for the checksum if different
      --timeout      max wait for stream in multicast client mode

server  are any of:
      --interface  Use 'if' as the interface for the server's
                       outgoing stream
      --config  server configuration file in plist format

imagescan  are any of:
      --filechecksum calculate file checksum
      --nostream     don't reorder file for multicast streaming
      --SHA1         add a SHA-1 checksum to the image

However, when you run FULL_USAGE=1 asr help, you get the following output:

Usage: asr  
   is one of the following:
    asr help | version
    asr restore --source  --target  []
    asr restore --source asr:/// --file  []
    asr server  --source  --config  []
    asr imagescan --source  [--filechecksum] [--nostream] [--SHA1]
    asr partition --target  [--testsize ]
                           [--retestsize ] [--recoverysize ]
    asr freeze --target  [--testsize ]
                        [--retestsize ] [--recoverysize ]
    asr thaw --target  [--recovery] [--modifyrecovery]
    asr adjust --target  [--settype ]
   is in bytes but may end with a scale factor (b, k, m, g)

common  are any of:
      --source  path or url to disk image file, mountpoint, or
                        web accessible disk image
      --puppetstrings   print out messages in format good for machine parsing
      --verbose         display verbose output
      --debug           display debug output

restore  are any of:
      --target  path to volume or mountpoint
      --hidden          restore to the hidden customer software partition
      --erase           formats target volume
      --format  target format when erasing (defaults to source)
      --noprompt        don't require confirmation on erase
      --noverify        don't checksum results
      --buffers    number of buffers to use in block copy
      --buffersize   size of buffers to use in block copy
      --csumbuffers   number of buffers for the checksum if different
      --csumbuffersize  size of buffers for the checksum if different
      --timeout      max wait for stream in multicast client mode

server  are any of:
      --interface  Use 'if' as the interface for the server's
                       outgoing stream
      --config  server configuration file in plist format

imagescan  are any of:
      --filechecksum calculate file checksum
      --nostream     don't reorder file for multicast streaming
      --SHA1         add a SHA-1 checksum to the image

There are now four additional options listed:

    asr partition --target  [--testsize ]
                           [--retestsize ] [--recoverysize ]
    asr freeze --target  [--testsize ]
                        [--retestsize ] [--recoverysize ]
    asr thaw --target  [--recovery] [--modifyrecovery]
    asr adjust --target  [--settype ]

The question I don’t know the answer to is “What do these options do?”

I’ve seen asr adjust used to correct an incorrectly set Recovery HD partition, but I’m not familiar with what asr freeze and asr thaw do.

Do you know? Let me know in the comments.