Undoing Your Last Change
Editing a File
Restoring from a Backup File
VLISP supports the automatic creation of backup copies of files loaded by the text editor. The actual backup creation occurs when you save the file for the first time. Backup files have the same name as your original file, except the file extension begins with an underscore (_) and is followed by the first two characters of the original extension. For example, the backup file for drawline.lsp would be drawline._ls.
Automatic creation
of backup files is an option you can set by choosing Tools 
Environment
Options General Options. Choose the Editor option labeled
Backup the File Edited on First Save to turn on automatic backup.
By default, this option is already selected when you first install
VLISP.