BASH Finding palindromes in a .txt file

Question

I have been given a .txt file in which we have to find all the palindromes in the text (must have at least 3 letters and they cant be the same letters e.g. AAA)

it should

Answer 1

# modify this to your needs; it should take your input on stdin, and return one word per
# line on stdout, in the same order if called more than once with the same input.
preprocess() {
  tr -d '[[:punct:][:digit:]@]' \
    | sed -E -e '/^(.)\1+$/d' \
    | tr -s '[[:space:]]' \
    | tr '[[:space:]]' '\n'
}

paste <(preprocess <"$1") <(preprocess <"$1" | rev) \
  | awk '$1 == $2 && (length($1) >= 3) { print $1 }' \
  | sort | uniq -c

The critical thing here is to paste together your input file with a stream that has each line from that input file reversed. This gives you two separate columns you can compare.