BASH Palindrome Checker

Question

This is my first time posting on here so bear with me please.

I received a bash assignment but my professor is completely unhelpful and so are his notes.

Our assig

Answer 1

Like this:

for word in `grep -E '^[a-z]{3,45}$' /usr/share/dict/words`;
    do [ $word == `echo $word | rev` ] && echo $word;
done;

Output using my dictionary:

aha
bib
bob
boob
...
wow

Update

As pointed out in the comments, reading in most of the dictionary into a variable in the for loop might not be the most efficient, and risks triggering errors in some shells. Here's an updated version:

grep -E '^[a-z]{3,45}$' /usr/share/dict/words | while read -r word;
    do [ $word == `echo $word | rev` ] && echo $word;
done;