Eval does arithmetic from the command line. For example, eval 2*3 prints the answer 6. Eval accepts the following infix binary operators: + add - subtract * multiply / divide \ mod (remainder of integer division) ^ power max maximum min minimum Parentheses may be used for grouping. Eval also accepts the following unary prefix operators: + unary plus - unary minus abs absolute value round rounding to integer trunc truncating to integer sqrt square root sqr square sin \ cos \ tan trig functions in radians arcsin for example, eval sin 3.14159265 prints 0.00000000358979 arccos and eval sin(3.14159265 / 2) prints 1 arctan \ sinh \ cosh \ tanh \ ln natural log log base 10 log log2 base 2 log exp raise to a power fact factorial The expression evaluation code is derived from the public domain spreadsheet included with Turbo Pascal. Note that some versions of Microsoft pascal incorrectly decide that your pc has an 8087 or 80287 math coprocessor when in fact it doesn't. To check this, try a simple multiplication. If eval 2*3 says 2, rather than 6, set the environment variable set NO87=X in your autoexec.bat file. (I use a blank in place of the X.)