new to linux/Ubuntu/shell scripting . . .

[Toby Kelsey]

Rachael C. wrote:
> Again, thanks to everyone who has been giving me lot of helpful info.  :D
> 
> If I want to also look for palindromes that are anywhere between 1 and
> 4 characters in length, what would I do?  I am looking at this : (^|\
> )([A-Za-z])([A-Za-z])\3\2($|\.|\ )  and I am not seeing how to break
> it down so I can find palindromes bigger or smaller than 4 character's
> in length. Could someone explain it to me?  I am very curious.  :)
> 
> Thanks!

Firstly I would suggest the matching pattern of

  \b([a-zA-Z])([a-zA-Z])\2\1\b

would be better. Do 'man grep' to find out what '\b' does. You could
also use [:alpha:] in there.

Secondly it should be easy to come up with patterns for 1, 2 and 3
letter palindromes based on that one.

Thirldy remember that

 this|that|theother

is a pattern which matches 'this', or 'that', or 'theother' and you can
build more complex patterns up from simple ones.

A  shell script works like the command-line. You can test commands out
by just typing them interactively at the prompt.

Hope this helps,
Toby