Use .bak file and implement signoff command.
tree1a524aa55e2a24823b86a21bc5ae8558119e27f6
-rw-r--r-- 24 .gitignore
-rw-r--r-- 188 Makefile
-rwxr-xr-x 12863 asure.py
-rw-r--r-- 889 hashing.py
-rw-r--r-- 1321 t_scan.py