graph.fnc

#!/bin/bash
## graph.fnc -- by Patsie
# Shell function that draws a graph with average line in ASCII
# The graph will have a width equal to the number of data points
# and a height equal to the first argument
# Usage: graph <height> <val1> [<val2> [<...>]]

# Taken from:
#    http://bashscripts.org/forum/viewtopic.php?f=7&t=1141
# and modified slightly for my own needs

function graph {
  height=$1; shift;

  echo "$@" | awk -v height=$height 'BEGIN { }
    ## convert big numbers to short kilo/mega/giga etc numbers
    function pow1k(bignum) {
      metric=1;
      num=bignum;

      # devide by 1000 until we have got a small enough number
      while (num>=1000) { metric++; num/=1000; }
      num=int(num);

      # get SI prefix (kilo, mega, giga, tera, peta, exa, zotta, yotta)
      si=substr(" KMGTPEZY", metric, 1);

      # get a division remainder to total our number of characters to a maximum of 4
      division=substr(bignum, length(num)+1, 3-length(num));

      # right align the output
      str=sprintf("%s%c%s", num, si, division);
      return(sprintf("% 4s", str));
    }
  {
    # get smallest, largest and total of all numbers
    min=max=tot=$1;
    for (x=2; x<=NF; x++) { tot+=$x; if ($x>max) max=$x; if ($x<min) min=$x; }

    # the difference between largest and smallest number is out working area
    diff=max-min;
    if (diff==0) diff=1;                                # all numbers are the same?!
    # some fancy math to get the average of all numbers
    avg=(tot/NF);
    avgfull=int(((avg-min)*height/diff));               # average full
    avghalf=int(((avg-min)*height/diff)%1+0.5);         # average half

    # fill arrays bars
    for (x=1; x<=23; x++) {
      v=$x-min;                                         # our value
      i=0;array[x]="";                                  # blank the array
      full=int((v*height/diff));                        # how many full?
      ttrd=int((v*height/diff)%1+0.333);                # 2/3rd full?
      otrd=int((v*height/diff)%1+0.666);                # 1/3rd full?
      while (i<full)   { array[x]=array[x]"#"; i++; }   # fill all fulls
      #while (i<full)   { array[x]=array[x]"O"; i++; }   # fill all fulls
      if    (ttrd>0)   { array[x]=array[x]"#"; i++; }   # fill 2/3rd
      #if    (ttrd>0)   { array[x]=array[x]"o"; i++; }   # fill 2/3rd
      else if (otrd>0) { array[x]=array[x]"#"; i++; }   # or 1/3rd
      #else if (otrd>0) { array[x]=array[x]"."; i++; }   # or 1/3rd

      # average line or blank
      while (i<height) {                                # fill to the top
         if (i==avgfull)                                # with average line
           if (avghalf>0) array[x]=array[x]"-";
           else array[x]=array[x]"_";
         else array[x]=array[x]" ";                     # or mostly blanks
         i++;
      }
    }

    # display output
    for (y=height; y>0; y--) {
      line=""; num="    ";                              # blank line and number
      if (y==avgfull+1) { num=pow1k(int(avg)); }        # show average number
      if (y==height)    { num=pow1k(max); }             # show maximum number
      if (y==1)         { num=pow1k(min); }             # show minimum number

      for (x=1; x<=23; x++)                             # do for all data values
        line=line""substr(array[x],y,1);                # create line from arrays
      printf(" %s | %s | %s\n", num, line, num);        # display 1 line
    }
  }'

}