DIGITAL RESEARCH(r) CP/M Plus TM (CP/M Version 3) Operating ...

6.6 Advanced ED Commands CP/M 3 User's Guide
To execute an H command, ED first finalizes the new file, transferring all lines
remaining 'in the buffer and the source file to the new file. Then ED closes the new
file, erases any BAK file that has the same file specification as the original source file,
and renames the original source file filename.BAK. ED then renames the new file,
which has had the filetype $$$, with the original file specification. Finally, ED opens
the newly renamed file as the new source file for a new edit, and opens a new $$$
file. When ED returns the * prompt, the CP is at the beginning of an empty memory
buffer.
If you want to send the edited material to a file other than the original file, use the
following command:
A>ED filespec differentfilespeo
If you then restart the edit with the H command, ED renames the file differentfilename.$$$
to differentfilename.BAK and creates a new file of differentfilespec when
you finish editing.
The 0 (Original) Command
An 0 command abandons changes made since the beginning of the edit and allows
you to return to the original source file and begin reediting without ending the ED
session. The 0 command takes the form:
0
followed by a carriage return. When you enter an 0 command, ED confirms that
you want to abandon your changes by asking
0 (Y/N)?
You must respond with either a Y or an N; if you press any other key, ED repeats
the question. When you enter Y, ED erases the temporary file and the contents of the
memory buffer. When the * prompt returns, the character pointer is pointing to the
beginning of an empty memory buffer, just as it is when you start ED.
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