[TUHS] The most surprising Unix programs

Steve Nickolas usotsuki at buric.co
Wed Mar 18 01:40:52 AEST 2020

On Tue, 17 Mar 2020, ca6c at firemail.cc wrote:

> Doug McIlroy wrote:
>> dc
>> The math library for Bob Morris's variable-precision desk calculator
>> used backward error analysis to determine the precision necessary at
>> each step to attain the user-specified precision of the result. In
>> my software-components talk at the 1968 NATO conference on software
>> engineering, I posited measurement-standard routines, which could deliver
>> results of any desired precision, but did not know how to design one. dc
>> still has the only such routines I know of.
> dc, along with ed and I guess awk if we can put it here, is one of my
> favorite Unix programs that I use daily.  I don't even have a "normal"
> calculator installed.  It just smells like Unix.
> There is something sexy about reverse Polish notation.  I really do
> encourage everyone reading this to try dc as their "desk calculator"
> for some time.

I personally prefer bc.

Actually, I use GNU's bc on Windows and MS-DOS too.  (Unfortunately the 
traditional version wouldn't work on MS-DOS where it's just a filter to 


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