stan(1)							  stan(1)


NAME
       stan - stream analyser

SYNOPSIS
       stan [ -bhvV ] [ -f filter ] [ -n number ] [ -p patlen ] [
       file ... ]

DESCRIPTION
       Stan creates statistics about  the  content  of	files  or
       stdin.  This information can be used in many ways, e.g. to
       analyze encrypted data or measure the  quality  of  random
       numbers. The program expects a list of files at the end of
       the command line, if no files are specified standard input
       is used.

       Stan is able to create three different types of statistics

   General Statistics
       Stan uses the bytes of the input data to	 calculate  stan-
       dard statisic values.  It calculates the mean, the median,
       the deviation, chi-square test value, the entropy per byte
       and  the	 serial correlation coefficient.  If possible the
       corresponding characters are  printed  after  the  decimal
       value.

   Pattern Statistics
       Stan analyzes all patterns of the length patlen inside the
       data stream and outputs the range and counts of	patterns.

   Bit Statistics
       Bit  statistics	are  measured  using  runs.  Runs  are	a
       sequences of the same bit, therefore stan analyses 0  runs
       and  1  runs.  In  bit mode stan prints ratio of runs of a
       length to the next length. This analysis fits  the  pseudo
       random  number criteria G1 by Golomb. Stan also prints the
       ratio of 0 runs to 1 runs by the length of the runs,  this
       analysis refers to the second criteria G2 by Golomb.

OPTIONS
       -b
	      Enable  bit  mode.  Create bit statistics about the
	      stream.

       -h
	      Print a help screen to stderr.

       -v
	      Be verbose. In this mode stan prints verbose infor-
	      mation  about  the  analysing process and also dis-
	      plays progress information.  When	 analysing  large
	      files this is a usefull option in order to see what
	      acutally is happening.

       -V

	      Display the version.

       -f filter
	      Use  a  filter  before  passing  the  data  to  the
	      analysing process. The following filter may be used
	      to restrict the range of data.

		     0 No filter (default)

		     1 Analyse only printable characters.

		     2 Analyse only alphanumeric characters.

       -n number
	      Display number of patterns. The  default	value  is
	      10.  You	should keep this value rather small since
	      normally a lot of patterns will be found in a  data
	      stream.

       -p patlen
	      Analyse  patterns	 from  1  to  patlen  length. The
	      length of the pattern is measured in bytes.

USAGE
       The interpretation of output generated by Stan requires	a
       good mathematical / statistcal background. This manual can
       not focus on all aspects of interpreting statistical  val-
       ues.  The  general  statistics  are  covered by most books
       about statistics and analysis.  There  is  a  book,  Shift
       Register	 Sequences written by S.Goloumb (1967), with fur-
       ther information about interpreting the bit statistics.

       Some examples of stan can be found at the  stan	homepage,
       http://www.roqe.org/stan.


NOTES
       Stan  was  designed with efficency in mind, but if you are
       using a large patlen , i.e. 6 or above, you may	run  into
       memory problems, especially if you are analysing random or
       nearly random data. Just remember  that	there  are  256^6
       patterns of the length 6, which could require 281 terabyte
       of memory!

       If you discover bugs or have any improvements to stan con-
       tact  the  author  at kr@roqe.org. You can always grab the
       latest version of stan from http://www.roqe.org/stan.
