dc

dc (desk calculator) is a cross-platform reverse-Polish calculator which supports arbitrary-precision arithmetic. Written by Lorinda Cherry and Robert Morris at Bell Labs, it is one of the oldest Unix utilities, preceding even the invention of the C programming language. Like other utilities of that vintage, it has a powerful set of features but terse syntax. Traditionally, the bc calculator program (with infix notation) was implemented on top of dc. This article provides some examples in an attempt to give a general flavour of the language; for a complete list of commands and syntax, one should consult the man page for one's specific implementation. History dc is the oldest surviving Unix language program. When its home Bell Labs received a PDP-11, dcwritten in Bwas the first language to run on the new computer, even before an assembler. Ken Thompson has opined that dc was the very first program written on the machine. Basic operations To multiply four and five in dc (note that most of the whitespace is optional):