#!/bin/bash
ascii=
index=0
noNames=10                                              #No of names to generate
nameLength=10                                           #Length to generate (you said 10)
for(( i=65; i<=90; i++ ))                               #Add upper-case letters to 'ascii'
do
        ascii[$index]=$(echo $i | awk '{printf("%c",$1)}')
        index=$(( $index + 1 ))
done

for(( i=48; i<=57; i++ )) # Add numbers to 'ascii'
do
        ascii[$index]=$(echo $i | awk '{printf("%c",$1)}')
        index=$(( $index + 1))
done

for(( i=0; i<$noNames; i++))
do
	name=                                           #We'll store the name in here
	last=                                           #We'll store the index of the last 
                                                        #   character generated here
	for(( j=0; j<$nameLength; j++))
	do  
		num=$(( $RANDOM % $index ))             # Pick a random character index
		while [[ $num -eq $last ]]              #If it's the same as the last 
                                                        #  one...
		do
			num=$(( $RANDOM % $index ))     #... pick a new one!
		done
		last=$num                               #Update "last" to current value
	        name=${name}${ascii[$num]}              #Add the correct letter to our name
	done
	echo "${name}"                                  #Print name...
done > output                                           #...to our output file

#!/usr/bin/awk -f

BEGIN{
    for(i = 48;i <=90;i++){
        if(i == 58)i+=7
        arr[++c] = sprintf("%c", i)
    }

    printf "Enter length of name to generate: "
    getline namelen < "-"

    srand()
    for(i = 1;i <= namelen;i++){
        do
            char = arr[1 + int(rand() * c)]
        while( char == substr(name, length(name)))

        name = name char
    }

    print name
}

while true
  s=rand(36**10).to_s(36)
  if s !~ /(.)\1/
    puts s
    break
  end
end

crunch [CRUNCH_OPTIONS] | grep -Ev '(.)\1'

0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ

ABAB
ABAC
ABCA
ABCB
ACAB
ACAC
ACBA
ACBC
BABA
BABC
BACA
BACB
BCAB
BCAC
BCBA
BCBC
CABA
CABC
CACA
CACB
CBAB
CBAC
CBCA
CBCB

#!/usr/bin/clisp

(defparameter *character-set* "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ")
;(defparameter *character-set* "ABC")     ; < --- this line is for testing

(defparameter *word-length* 10)
;(defparameter *word-length* 4)           ; < --- this line is for testing

(defparameter *character-list*
   (coerce *character-set* 'list))

(defun final-char (in-string)
   (cond
      ((> (length in-string) 0)
         (elt in-string (1- (length in-string))))
      (t
         nil)))

(defun new-char-list (in-string)
   (let ((result))
      (mapcar
         (lambda (candidate)
            (cond
               ((not (eql candidate (final-char in-string)))
                  (push candidate result))))
         *character-list*)
      (nreverse result))
      )

(defun extend-string (in-string desired-length)
   (mapcar
      (lambda (new-char)
         (let ((new-string (concatenate 'string in-string (string new-char))))
            (cond
               ((>  (length new-string) desired-length))
               ((>= (length new-string) desired-length)
                  (format t "~a~%" new-string))
               (t
                  (extend-string new-string desired-length)))))
      (new-char-list in-string)))

(extend-string "" *word-length*)

#!/usr/bin/awk -f

BEGIN{
#    set = "0 1 2 3 4 5 6 7 8 9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z"
    set = "A B C D"

    n = split(set, chars)

    printf "Enter length of name to generate: "
    getline namelen < "-"

    if(namelen ~ /^[0-9]+$/)
        n = namelen

    print_string("", chars, n)

}

function print_string( string, array, len,      local_array, i, c)
{
    for(i in array)
        if(array[i] != substr(string,length(string)))
            local_array[++c] = array[i]

    for(i in local_array)
        if(length(string) + 1 == len)
            print string local_array[i]
        else
            print_string(string local_array[i], array, len)
}