Shell Programming and Scripting

block 1: "Abcd"
block 2: "efg"
block 3: "hij1"

"Abcd" "efg" "hij1"
"Acbd" "feg" "h1ji"
"Adbc" "fge" "j1hi"
...

#!/usr/bin/env perl

# @(#) p2	Demonstrate combinations and permutations.

use Math::Combinatorics;

my @n = qw(a b c);
print "combinations of 2 from: " . join( " ", @n ) . "\n";
print "------------------------" . ( "--" x scalar(@n) ) . "\n";
print join( "\n", map { join " ", @$_ } combine( 2, @n ) ), "\n";
print "\n";
print "permutations of 3 from: " . join( " ", @n ) . "\n";
print "------------------------" . ( "--" x scalar(@n) ) . "\n";
print join( "\n", map { join " ", @$_ } permute(@n) ), "\n";

exit(0);

% ./p2
combinations of 2 from: a b c
------------------------------
c a
c b
a b

permutations of 3 from: a b c
------------------------------
a b c
a c b
b a c
b c a
c a b
c b a

#!/usr/dt/bin/dtksh

CHARSET="Abcdefghij1"
integer ctr=10  # Number of times to loop.

# Arrays for original blocks
set -A a_block1
set -A a_block2
set -A a_block3

# Arrays for new mixed blocks
set -A na_block1
set -A na_block2
set -A na_block3

# Split CHARSET into the original blocks.
for (( i=0;i<4;i++ ))
do
  a_block1[${i}]=${CHARSET:${i}:1}
done
for (( i=0;i<3;i++ ))
do
  a_block2[${i}]=${CHARSET:${i}+4:1}
done
for (( i=0;i<4;i++ ))
do
  a_block3[${i}]=${CHARSET:${i}+7:1}
done

#  Print out starting blocks.
print "Block 1: \"${a_block1[0]}${a_block1[1]}${a_block1[2]}${a_block1[3]}\""
print "Block 2: \"${a_block2[0]}${a_block2[1]}${a_block2[2]}\""
print "Block 3: \"${a_block3[0]}${a_block3[1]}${a_block3[2]}${a_block3[3]}\""
print

##  Function to generate a random number between 1 and the number passed
##  in inclusive. Sets $random_nbr.
get_random_nbr() {
  if [[ $1 == 0 ]]; then
    return 1
  else
    random_nbr=$(( ($RANDOM % $1 ) +1 ))
  fi
}

#  Mix 'em up.  Jumble each block, copying into the new mixed array. Do it for each
# block.  This should be made into a function but I just repeated it to get done quicker.

for (( k=0;k<${ctr};k++ ))
do
  # For the length of the array...
  for (( i=0;i<${#a_block1[*]};i++ ))
  do
    # Get a random number...
    get_random_nbr ${#a_block1[*]}
    (( j=$random_nbr -1 ))

    # Use the random number as an index into the mixed array and see if
    # it is not null.
    while [[ -n ${na_block1[${j}]} ]]
    do
      # if not null, get another random number until the array location is null.
      get_random_nbr ${#a_block1[*]}
      (( j=$random_nbr -1 ))
    done

    # The character at the index is null so plug in the character
    # from the original array.
    na_block1[${j}]=${a_block1[${i}]}
  done

  for (( i=0;i<${#a_block2[*]};i++ ))
  do
    get_random_nbr ${#a_block2[*]}
    (( j=$random_nbr -1 ))

    while [[ -n ${na_block2[${j}]} ]]
    do
      get_random_nbr ${#a_block2[*]}
      (( j=$random_nbr -1 ))
    done
    na_block2[${j}]=${a_block2[${i}]}
  done

  for (( i=0;i<${#a_block3[*]};i++ ))
  do
    get_random_nbr ${#a_block3[*]}
    (( j=$random_nbr -1 ))

    while [[ -n ${na_block3[${j}]} ]]
    do
      get_random_nbr ${#a_block3[*]}
      (( j=$random_nbr -1 ))
    done
    na_block3[${j}]=${a_block3[${i}]}
  done

  print "\"${na_block1[0]}${na_block1[1]}${na_block1[2]}${na_block1[3]}\" \c"
  print "\"${na_block2[0]}${na_block2[1]}${na_block2[2]}${na_block2[3]}\" \c"
  print "\"${na_block3[0]}${na_block3[1]}${na_block3[2]}${na_block3[3]}\""

  # Clear the new array blocks for the next run.
  set -A na_block1
  set -A na_block2
  set -A na_block3

done

exit 0

$ efs
Block 1: "Abcd"
Block 2: "efg"
Block 3: "hij1"

"Adbc" "egf" "h1ji"
"Abcd" "feg" "h1ij"
"cdbA" "feg" "hj1i"
"cdAb" "gfe" "jhi1"
"cdbA" "egf" "ji1h"
"dbcA" "feg" "ij1h"
"Acdb" "egf" "h1ij"
"bdcA" "gef" "h1ji"
"bdcA" "egf" "ji1h"
"bcdA" "gef" "ji1h"
$