A brief help message which includes the list of default constants
and functions is printed by 'calc -h'
Calc works in two modes, command-line and standard input.
In the command line mode, you supply the expression as the
command-line argument. This expression is evaluated and
the result is printed. For example:
% calc 10mp/(mp+me)
In the standard input mode, you call calc without an
argument, and then type the statements. For example
When trying this example, notice that only statements that don't
contain an assignment (the '=' sign) get printed
Private constants and functions may be declared by the user. Put
the Perl code into a file and point the environment variable CALCRC
to this file. Your code will be executed right after the default
constants and functions are declared (so you can overwrite them).
You can additional control the script behavior by two enviroment
CALCDEBUG if set and non-zero, tells the script to
print the expression that gets evaluated. So you are able to
control how the script interprets your expressions
CALCFORMAT overwrites a default format for printing
the values, "%g"