AmigaOS uses AmigaDOS
AmigaDOS
AmigaDOS provides the disk operating system portion of the AmigaOS. This includes file systems, file and directory manipulation, the command-line interface, file redirection, console windows, and so on. Its interfaces offer facilities such as command redirection, piping, scripting with structured programming primitives, and a system of global and local variables.
In AmigaOS 1.x, the AmigaDOS portion was based on TRIPOS, which is written in BCPL. Interfacing with it from other languages proved a difficult and error-prone task, and the port of TRIPOS was not very efficient.
From AmigaOS 2.x onwards, AmigaDOS was rewritten in C and Assembler, retaining 1.x BCPL program compatibility, and it incorporated parts of the third-party AmigaDOS Resource Project, which had already written replacements for many of the BCPL utilities and interfaces.
ARP also provided one of the first standardized file requesters for the Amiga, and introduced the use of more friendly UNIX-style wildcard (globbing) functions in command-line parameters. Other innovations were an improvement in the range of date formats accepted by commands and the facility to make a command resident, so that it only needs to be loaded into memory once and remains in memory to reduce the cost of loading in subsequent uses.
In AmigaOS 4.0, the DOS abandoned the BCPL legacy completely and, starting from AmigaOS 4.1, it has been rewritten with full 64-bit support.
File extensions are often used in AmigaOS, but they are not mandatory and they are not handled specially by the DOS, being instead just a conventional part of the file names. Executable programs are recognized using a magic number.