System information

DIR X.*Checks to see that BAK file is available.
ERA X.ASMErases most recent version.
REN X.ASM=X.BAKRenames the BAK file to ASM.
You can abort the edit at any point (reboot, power failure, CTRL-C, or CTRL-Q command)
without destroying the original file. In this case, the BAK file is not created and the original file
is always intact.
The ED program allows the user to edit the source on one disk and create the back-up file on
another disk. This form of the ED command is
ED ufn d:
where ufn is the name of the file to edit on the currently logged disk and d is the name of an
alternate drive. The ED program reads and processes the source file and writes the new file to
drive d using the name ufn. After processing, the original file becomes the back-up file. If the
operator is addressing disk A, the following command is valid.
ED X.ASM B:
This edits the file X.ASM on drive A, creating the new file X.$$$ on drive B. After a successfuI
edit, A:X.ASM is renamed to A:X.BAK, and B:X.$$$ is renamed to B:X.ASM. For
convenience, the currently logged disk becomes drive B at the end of the edit. Note that if a file
named B:X.ASM exists before the editing begins, the following message appears on the screen:
FILE EXISTS
This message is a precaution against accidentally destroying a source file. You should first erase
the existing file and then restart the edit operation.
1.6 Transient Commands CP/M Operating System Manual
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