Ever create a Zip file and then realize that you want more files and or folders in the Zip file? What if they were elsewhere on the hard drive, in a different directory, or even on a different drive?
That’s no problem with 7-Zip.
Let’s start with a Zip file containing the same files as used in my article 7-Zip — a Free File Archiver. We’re going to add another directory of files and folders into the existing Zip file that I had created.
The first thing to do is to use the Up Directory button to move to the directory containing the files or folders that you want to add to the existing directory.
In this case, I’ve moved to the folder E:\Data\Coffee\espresso_machines\ so that I can add a huge folder of documents relating to my espresso machine into the TV.zip file.
My first step is to select the folder that I want to add to the Zip file. Then, I need to click on the Add button.
The first thing I need to do is to change the Archive Format setting from the default 7z to Zip. Just use the pull-down option bar to select zip.
Then, notice where the archive file will be created. By default, it will be created within the current directory.
However, in this case, we want to add the folder and files into an already-existing Zip file that’s located in another directory.
Notice that there is a button labelled "…" at the right end of the Archive location box. Click on that button.
That will open a standard Windows file/folder selection dialog box.
I used the resulting dialog box to identify that I wanted to use the archive folder TV.zip that was located in folder E:\Data\TV.
At that point, click the OK button to add the folder into the existing Zip file.
Below, I’ve moved back to the TV directory to show the size of the TV.zip file, now that the huge directory has been added to it.
Now, we take a look inside the TV.zip file. Here, we can see how well each file has been compacted.
The effectiveness of compacting (packing) in the zip file (or any other type of archive file) depends on the compactability of the files being packed into the archive file.
Some file types are much less efficient than others, so they lend themselves to efficient packing more easily. PDF files, MP3 files, and MPG files, on the other hand, are already stored in efficiently packed formats and, therefore, benefit little from zipping.
On the other hand, the other big advantage of archive files is that they can retain the directory/sub-directory structure, and not just a bunch of individual files.