# Add content to an existing .zip file

I have been looking over the .zip documentation from Mathematica (http://reference.wolfram.com/mathematica/ref/format/ZIP.html). It seems pretty straighforward to export and import from/to a .zip file, but how can i add content to an existing .zip file?

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you need to import the whole thing, add your content and re-export. –  george2079 Mar 30 at 0:42
This question appears to be off-topic because it concerns the structure of zip files in a way that is not specific to Mathematica. –  m_goldberg Mar 30 at 1:45
@m_goldberg while it may not work out of the box the question is still valid and perhaps someone will come up with a clever solution. –  Yves Klett Mar 30 at 12:09
the zip format is open. You'll need to read and reconstruct the central directory to include reference to your new file. Seems do-able, on the other hand there are plenty of simple command line utilies that already do this so why reinvent the wheel? stackoverflow.com/questions/4802097/… –  george2079 Mar 30 at 13:13
Since there are utility apps available that can add a file or files to an existing .zip, and at least "out of the box" Mathematica cannot do such, it doesn't seem off-topic to have the question here. –  murray Mar 30 at 15:59