Edit: Hopefully this is just a review.
Originally posted February 26, 2019 on AIXchange
Awhile back Shivaprasad Nayak tweeted about AIX system files.
Here’s a glimpse from the IBM Knowledge Center:
The files in this section are system files. These files are created and maintained by the operating system and are necessary for the system to perform its many functions. System files are used by many commands and subroutines to perform operations. These files can only be changed by a user with root authority.
There are three basic types of files:
All file types recognized by the system fall into one of these categories. However, the operating system uses many variations of these basic types.
Regular files are the most common. When a word processing program is used to create a document, both the program and the document are contained in regular files.
Regular files contain either text or binary information. Text files are readable by the user. Binary files are readable by the computer. Binary files can be executable files that instruct the system to accomplish a job. Commands, shell scripts, and other programs are stored in executable files.
Directories contain information the system needs to access all types of files, but they do not contain the actual file data. As a result, directories occupy less space than a regular file and give the file-system structure flexibility and depth. Each directory entry represents either a file or subdirectory and contains the name of a file and the file’s i-node (index node reference) number. The i-node number represents the unique i-node that describes the location of the data associated with the file. Directories are created and controlled by a separate set of commands.
Special files define devices for the system or temporary files created by processes. There are three basic types of special files: FIFO (first-in, first-out), block, and character. FIFO files are also called pipes. Pipes are created by one process to temporarily allow communication with another process. These files cease to exist when the first process finishes. Block and character files define devices.
Scroll down and you’ll see a list of many files you should be familiar with.
Also check out the parent web page, “Files Reference”:
This topic collection contains sections on the system files, special files, header files, and directories that are provided with the operating system and optional program products. File formats required for certain files that are generated by the system or by an optional program are also presented in this topic collection.
This is all good information, so I wanted to pass it along.