Help with Informatica Backend Shell Script

Request Any one of your to provide me a script which does the following in a single unix script.

Basically Users will load data in SHARED LINK everyday, should write a UNIX SCRIPT which will ........
1) Unix script should Open the LINK (FTP)
2) Each DIRECTORY in the link contains many .tar.gz (gunzipped) FILES
3) We have to unzip one by one and save into a temporary folder (each unzipped .tar file will have many .unl files)
4)We need to read the data from only three(3) .unl files out of all the available .UNL files in each extracted folder, lets say a.unl, b.unl and c.unl from a folder ABC.tar

I tried a lot with many people across the globe, but couldn't get a proper answer. Came to know about UNIX.com and came here to seek your kind help.