AT&T dc

From Rosetta Code
AT&T dc is an implementation of dc. Other implementations of dc.

The original dc interpreter appeared in Version 1 (V1) AT&T UNIX. Therefore, dc precedes the C language (appeared in V3 UNIX) and the Bourne Shell (appeared in V7 UNIX). The authors programmed the interpreter in PDP-11 Assembly, and later rewrote it in C language. AT&T dc became the back end of AT&T bc in V6 UNIX. AT&T dc survives in systems that descend from System V, including Solaris.

POSIX only describes bc, not dc; so AT&T dc is the only reference. Other implementations (like GNU dc and OpenBSD dc) follow AT&T dc by implementing the same commands.

The manual page accidentally omits !< != !>, but AT&T dc does have these commands, and dc programmers do use them.

Ancient dc

The Unix Heritage Society preserves old versions of AT&T UNIX.

Modern dc

The Heirloom Project provides AT&T dc along with other System V commands.