[TUHS] The most surprising Unix programs

ca6c at firemail.cc ca6c at firemail.cc
Tue Mar 17 23:03:41 AEST 2020

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.

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