How to combine / merge zip files?

you won't like it but: unzipping everything into a working folder in the right order, then zipping the result is the most effective way.

otherwise, you will end up with a lot of wasted CPU cycles:

• assume your result goes to 'first.zip'
• every file from '2.zip', '3.zip' etc has to be unzipped and then zipped again into 'first.zip'
• in '2.zip' exists a file 'foobar.txt' and in '3.zip' exists another file 'foobar.txt'. merging it the way you want to merge it leads to 'compress it X times'
• the toc of a .zip is at the end of the file: you add more content (to the middle of the
  .zip by updating a file in the middle) and the whole file has to be rewritten

so, imho just use 'unzip' wiseley:

% mkdir all
% for x in *.zip ; do unzip -d all -o -u $x ; done
% zip -r all.zip all

the order of the unzipping is important, I don't know the pattern of your zip names, but I would extract the newest zip file first, the '-u' option of unzip overwrites only files if they are newer or creates files if not already there. as a result, you will unzip only the newest files and zip the result only once.

It may not be what you're looking for, but the free Ant build tool does include the ability to merge Zipfiles.

https://ant.apache.org/manual/Tasks/zip.html

Just use the -g option of ZIP, where you can append any number of ZIP files into one (without extracting the old ones). This will save you significant time.

Also have a look at zipmerge