Restoring the History File

In particularly bad circumstances, the history file itself can become corrupted, usually by someone editing it. Since the file contains a checksum, you will get errors every time you read a corrupted file. To correct the checksum, use:

$ sccs admin -z program.c

When SCCS says that the history file is corrupted, it may indicate serious damage beyond an incorrect checksum. Be careful to safeguard your current changes before attempting to correct a history file.