Title:           [Bash] flash detector
Author:          Anonymous
Pastebin link:   http://pastebin.com/1GWQejEQ
First Edit:      Sunday 20th of July 2014 09:24:21 AM CDT
Last Edit:       Sunday 20th of July 2014 09:24:21 AM CDT

#!/bin/bash
file=$1
color1=$2
color2=$3
color3=$4
tolorance=10
amount=50
#echo "$file $color1 $color2 $color3"
convert $file -colors 256 -depth 8 -format "%c" histogram:info: | # produces histogram
        sort -g -r | #sort by amount
        head -n $amount | #takes only $amount first colors
        sed 's/^.*#[^(]*//g  
s/[()]//g
s/,/ /g' |  #changes the line to 'R G B' (each 0-255)
while read x   # reads the individual lines
do echo $x | sed 's/ /\n/g' | (  # puts R G B on separate lines and sends to subprocess
        read R  
        read G
        read B
       # echo "$R $G $B"
        RA=`expr $R - $color1`  # difference between tested color and 'line' color
        GA=`expr $G - $color2`
        BA=`expr $B - $color3`
        if      [ $A -le $tolerance ] &&  
                [ $A -le $tolerance ] &&
                [ $A -le $tolerance ] &&
                [ $A -ge "-$tolerance" ] &&
                [ $A -ge "-$tolerance" ] &&
                [ $A -ge "-$tolerance" ]
                then echo true  # checks wheter the difference is tolerable
                exit 0
        fi
        #echo false
        exit 1
        ) 2> /dev/null
if [ $? -eq 0 ] # if the subprocess returned 0 (contains color), I return it too
then exit 0
fi
done
exit 1