Zip stored 0%, should I be concerned?

Question

I am using zip to archive a lot of files. There are a few files I have that are small (they just contain one decimal number stored on one line). After operating on these files, zip reports stored 0%. Not deflated 0%, but stored 0%. I am wondering if this means that my subsequent zip archive will not have these files stored. If so, is there any way I can fix it so zip will store them? Is it because the files are so small?

Answer 1

When zip add a file, it will compress it if it makes sense.

If the file is big enough, zip will use the compression algorithm DEFLATE (and print "deflated" and the % gained with the compression).

For very small files the compression will make the result bigger (for example, if I manually deflate a file with 2 bytes, I will get 4 bytes) so zip decides to STORE them (no compression) : it prints "stored" and 0% because this "compression" didn't change the size. zip will also STORE folders (no content).

You can easily play with the compression : zip -0 will STORE everything, zip -1 to zip -9 will change the compression level of DEFLATE and zip -Z bzip2 will change the compression method.

So, to answer to your question : the stored 0% is fine ! The file has been added but not compressed.

Answer 2

Do you run zip with recursion option?

zip -r output.zip folder

Without -r, the zip will not compress with sub-directories and lead to deflated 0%.