installing multiple addons with similar files

I have a simple question that has been bugging me all day.

If i have, say for example, two new addons that I want to install, but both of them share some files. How do i install them both?

Like when I tried installing a captcha addon AND an automatic login addon, one just overwrites the other.

I tried using my *nix diff command and then patching afterwards, but I jsut cannot seem to do it..

Anyone explain to me, in relatively simple steps, how I should go about installing addons that share files, without overwriting the others each time??

Please tell me i don't have to manually see what lines are different, and then work from there....:yuck:

chemibase:

Please tell me i don't have to manually see what lines are different, and then work from there....
Yes, you do. :blush:
WinMerge / KDiff / BBedit are handy utilities for quickly identifying merge requirements.

i just installed KDiff.
say I install the Auto-Login addon,
can I use KDiff to merge the files shared by this and any other addon I want to install?

uhm..what I mean is can I merge addons together?

Like if two addons I wnated had foobar.php to be copied to the server, could I merge them together and THEN upload the result to the server, giving me both files in one??

Yes. Identify the differences, and merge their differences into one file, and upload that file to the server. It's best to be sure they're both based on the same version to start with though.

Recommended rule-of-thumb: if several addons are clashing on several files, I suggest reconsidering whether you really need those addons or not.
Don't just install addons "because you can". Instead, carefully consider the business-reason for using it, and only install it if it's really needed.

thanks for the input DrByte. much appreciated.
I have been considering careefully what is worth installing and what is better off left, and most of the time I am choosing whether the thing I am installing is useful enough to be worth it. Such as auto-login or CAPTCHA. Especially security stuff like captcha.