bc is a language that supports arbitrary precision numbers with
interactive execution of statements. There are some similarities in
the syntax to the C programming language. A standard math library is
available by command line option. If requested, the math library is
defined before processing any files. bc starts by processing code from
all the files listed on the command line in the order listed. After
all files have been processed, bc reads from the standard input. All
code is executed as it is read. (If a file contains a command to halt
the processor, bc will never read from the standard input.)
This version of bc contains several extensions beyond traditional bc
implementations and the POSIX draft standard. Command line options can
cause these extensions to print a warning or to be rejected. This
document describes the language accepted by this processor. …