.BUF File Extension
What is a BUF file?
A BUF file is a buffer file used by various programs, such as SQL*Plus and GNU Emacs. It contains data for a short time and then is erased. BUF files are not meant to be opened.
BUF files are temporary, which means you will most likely not come across a BUF file. If you do, do not try to open the file, it is only meant to be used to store data for its corresponding application for a short amount of time. For example, BUF files are used by SQL*Plus to store the most recently entered PL/SQL block or SQL command and then are replaced by the next command or block.