recovery Switch

The recovery switch turns on ZMODEM "crash recovery." Crash recovery allows a file transfer to resume in midstream or mid-file after being canceled or interrupted, without retransferring the part of the file that has already been received.

If the file does not already exist on the destination system, it will be transferred in its entirety. Files that already exist but are shorter on the destination will be appended to, beginning with the first byte of the original file beyond the length of the destination file (allowing an interrupted transfer to pick up from mid-file).

Some ZMODEM programs compare the hash codes of the part of the file that already exists to make sure the original and the destination copies are identical. (This may be called -rr or second-level crash recovery.) Autolog will use second-level crash recovery if you use both the hash and recovery switches together.

If the existing destination file is longer than the original, the action taken depends on the receiving ZMODEM program. Autolog will allow an existing, longer file to be replaced entirely by a new, shorter file when downloading with zreceive/recovery.

The recovery switch can be used with these file transfer commands:
 

ztransmit and zreceive

Note You may not use the text switch in combination with the recovery switch.

Note If the file name was truncated or altered to make it valid on the destination system, crash recovery is always disabled to prevent accidentally overwriting files that are not truly identical but that ended up with the same name coincidentally.