Bash script to randomly permute every occurrence of a word in a file.

scramble_file.sh

#!/bin/sh

Perm () {
  A=$1
  i=0
  while [ $i -lt ${#A} ]; do y[$i]=${A:$i:1};  i=$((i+1));done
  s=`shuf -e ${y[@]}`
  newString=''
  s=$(sed 's|\ ||g' <<< $s)
  i=0
  while [ $i -lt ${#s} ];
    do
    nextChar=${s:i:1}
    newString+=$nextChar
    i=$((i+1))
    done
  eval "$2='$newString'"
}

# USAGE
# Perm $old_string new_string

if [ "$#" -ne 3 ]; then
  echo "ERROR, ILLEGAL NUMBER OF ARGUMENTS"
  echo "USAGE: ./string_scramble.sh inFile.txt string_to_randomize outFile.txt"
  exit 1
fi

while read LINE
  do
  num=`echo $LINE | grep -o "$2" | wc -l`
  replace_string=''
  j=1
  num=$((num+1))
  while [ $j -lt $num ];
    do
    Perm $2 replace_string
    newline=$(sed 's|'$2'|'$replace_string'|1' <<< $LINE)
    LINE=$newline
    j=$((j+1))
  done
echo $LINE >> $3
done < $1