7. File Recovery

To recover from a journal file, restart the editor on the edited file as before, but with the input directed from the journal file. You will see the editing session replayed.

Example:

Suppose in your directory there is a file called "text.doc":

text.doc     Jun 6 1978   8:02

You begin editing the file " text.doc" by typing:

ed   text.doc

An hour into your editing session, the system crashes at 10:37 AM.

Upon resumption, you would notice there are two files:

text.doc     Jun 6 1978   8:02
text.jou     Jun 7 1978   10:36

The first file contains the original contents of the " text.doc" file prior to the crashed editing session. The " text.jou" file contains a record of the edits made during the recent session.

To be safe, make a copy of the journal file:

cp   text.jou   text.recover

You can now recover the edits from the interrupted editing session as follows:

Begin the recovery process by editing the "text.recover" file to put a control-Z and "exit" at its end so that the file will be saved upon recovery.

Specifically:

1. enter screen mode ( c ),
2. go to the end of the file (gold 4),
3. hit space and return,
4. enter the control character ctrl-Z by hitting in sequence:

   gold
   3
   26
   gold

   (26 is the ascii value for ^Z.)
   
5. enter "ex" after the ^Z. This will cause an exit and save the document when you execute the recovery file.
6. save and close the recovery file.

Now execute the recovery file by typing:

ed   text.doc   <   text.recovery

You will see the replay of your editing session and the editor will save the final version and close.

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