Oracle DBA – A lifelong learning experience

Performing calculations in unix

Posted by John Hallas on August 31, 2009

Normally if I working on a database and want perform simple calculations I use the Oracle database rather than starting up the windows calculator.

select 6*1024*1024 from dual;

6*1024*1024
-----------
    6291456

 

However I recently found out a method of using unix itself (I am sure there are many more options other than this one but I find this quite easy)

man bc gives

bc is an interactive processor for a language that resembles C but provides unlimited-precision arithmetic.  It takes input from any  files given, then reads the standard input.

In usage

/home/oracle $bc
6*1024*1024
6291456
quit

Arithmetic operators are shown in the normal manner + - * / % ^ and there are lots of functions available such as sine, cosine and log, although I would be likely to use a calculator if I wanted to use these.

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6 Responses to “Performing calculations in unix”

  1. danirey said

    Thanks for sharing. When using Linux with KDE I prefer to do calculations in the “run command” window (works only with KDE < Version 4)

    You can usually open the "run command" dialog with Alt+F2, or in the KDE Menu. If you want to proceed with results 0.2342 Otherwise it’s not recognized as a number.

  2. pgreenwood said

    I go to python for quick calculations.

    • John Hallas said

      Thanks Patrick, there are lots of ways of doing calculations using shell, perl, python bit I found bc nice and easy (and there is an alternative dc which looks very simple as well)

  3. lbolla said

    I strongly recommend you:
    $> bc -l

    otherwise 1/2 = 0, instead of 0.5!
    L

  4. [...] John Hallas – Performing calculations in unix [...]

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