GETDIFF - Get specific changes within local PC file system

Syntax:	GETDIFF	[ dbfile ]
Arguments:	[ dbfile ]	Optional Variable or string specifying a snapshot database file. If omitted, the default value is “snapshot_local.sql”. When [ dbfile ] is specified without a full path the alternate default path is used.
Options:	/commitlast	Mark current difference "done" on the next call to GETDIFF.

The DIFF and GETDIFF commands work together to identify and process changes to local files.

The GETDIFF command sets the values of five internal variables with details describing a change to a single local file. These details are pulled from a snapshot database where they were inserted by a previous call to the DIFF command. Subsequent calls to GETDIFF fetch the details of subsequent changes from the database. The GETDIFF command is typically used in a loop so that each detected change is processed during one iteration of the loop. Depending on your needs, the processing may involve one or more of the internal variables set by this command. It is possible for GETDIFF to report file changes in alphabetical order rather than folder hierarchical order depending on how the records are stored in the snapshot database. This command returns $ERROR_READ_EOF when there are no more differences in the database. The DIFFREWIND command is available to reset the file pointer to the first change recorded in the database.

If the [ dbfile ] argument is omitted, the default file name “snapshot_local.sql” file is used. An error occurs if the snapshot database file does not exist.

The GETDIFF command sets the values of the following variables that you can use in your script logic:

%difffileid	Type of change detected
%difffiletext	Text description of type of change detected
%difffilename	Name of changed file
%difffilepath	Full path of changed file
%diffnum	Sequential change number

$DIFF_FILE_NOT_FOUND	5001	** File not found
$DIFF_FILE_IS_NEW	5002	** File is new
$DIFF_FILE_SIZE	5003	** File size changed
$DIFF_FILE_DATETTIME	5004	** File date/time stamp changed

Here is a simple example that shows how GETDIFF might be used inside a loop to write a text file that lists all the changes found by DIFF:

The following example loops through all changes and uploads only the new files to a remote site:

If you need to restart the loop, use the DIFFREWIND command to reset the file pointer to the first difference recorded in the snapshot database.

Normally, each difference is marked "done" when GETDIFF retrieves it from the snapshot database. The /commitlast option increases fault tolerance by causing GETDIFF to only mark the previously retrieved difference done. This way, a difference may be processed twice instead of skipped if loop processing is interrupted after GETDIFF is called but before the full loop iteration is complete.

Note: Snapshot database files are small SQLite database files created by Robo-FTP to support the DIFF and FTPDIFF family of script commands.