Hello,
I'm using bash on Mac Terminal. I have two files with sequences that look like, for example:
File 1:
ABCDE11111112345
BERSD222222223453
ADSFAFG243234123

File 2:
ABCDE11111112345
ABCDE3453454
ADSFASDFF12345
ADSFASDGAS34123

I want to find similar sequences that are not only completely the same (like ABCDE11111112345), but also those that are the same in the first 5 or the last five characters. For example, ABCDE3453454 would count as the same as ABCDE11111112345 because the first 5 characters are both ABCDE. ADSFASDGAS34123 and ADSFAFG243234123 would count as the same before the last 5 characters are both 34123. And I want to search for all the "same" sequences from the two files.

Is there a way to do such a search?

Thank you!

Yes, it should be a way!
Do you mean: "do exist a way with system command / bash / programs?", do you?

I think that a similar "scanner" would require programming by yourself with a deep know of regular expression!
I would suggest you Perl as program language (and in that case I would happy to help you!).

Hope this helps!

You might want to look at awk and diff and regular expressions (aka regex).

I don't know enough to tell you how to do the search--still trying to learn those--but those tools sound appropriate to this issue, if they are available on your Mac.

See man awk and man diff for more. Wikipedia has an article on regex.

https://en.wikipedia.org/wiki/Regular_expression

More on awk: http://www.gnu.org/software/gawk/manual/gawk.html