.1 File Extension
What is a 1 file?
A 1 file contains a manual page (also known as "man page") used by the "man" utility, a Unix program utilized to view user manuals. It stores a level 1 user manual in plain text that is separated into several segments and delimited by standard markers.
Level 1 user manuals describe general commands for the Unix operating system. Each level 1 user manual is stored in a file that bears the same name as the command it describes followed by the .1 extension. For example, a manual describing the cmd_example command would have the filename cmd_example.1.
Unix man page files are commonly compressed into .GZ files and have the .gz.1 compound extension. Unix man pages also use the .2 through .8 extensions for other sections. For example, the .2 extension is used for System Calls documentation.
How do I open a 1 file?
You can open a 1 file with the "man" utility included with most Unix systems. Since Unix man pages are stored in a plain text format, you can also use a text editor, such as Microsoft Notepad (Windows) or Apple TextEdit (Mac) to view and edit 1 files.