as is a generic command name for an assembler on

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

Implementations

More than one assembler for Unix and Unix-like operating systems has been implemented with an executable called as. Users may be able to determine which implementation (if any) is present on their system by consulting the system's manuals, or by running as --version.

AT&T / Bell Labs

As of November 1971, an assembler invoked as as was available for Unix. Implemented by Bell Labs staff, it was based upon the

Digital Equipment Corporation Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until ...

's PAL-11R assembler.

GNU Assembler

Circa 1986, the GNU Assembler ("GAS") became available. As with the original UNIX assembler, GAS's executable is simply named as. As of 2018, GAS implements many features that were not present in the 1971 Bell Labs implementation.

References

Assemblers Unix programming tools {{Unix-stub