From the course: Computer Literacy for Mac (2018)

Compressing files - Mac OS Tutorial

From the course: Computer Literacy for Mac (2018)

Compressing files

“

- Regardless of the type of file you're sending to someone, if you're using the internet to send the file, whether by email or a web-based sharing service, another habit you should get into is compressing your files before emailing them. When it comes to the web, the file size still matters a lot and is a major determining factor in how long it takes to send and receive a file or whether you can send the file at all. Compressing a file does just what it sounds like: it makes the file smaller. Fortunately, Mac OS has the ability to compress files in the most popular compression format, the zip format. Let's see how it works. I have here on my desktop the exercise files folder for this course. Now I could easily open a new email message and drag all of these files into the message as separate attachments, but you're going to find that compressing multiple files into a single attachment generally results in all the files getting to their destination without corruption or errors much more frequently than sending everything uncompressed as individual attachments. But this doesn't say you shouldn't compress single files. Even if I were only sending a single word processing document, I would probably still compress it, especially if it's a large document. Word processors are notorious for not being very efficient with the amount of space their files take up. So, to zip up these files, I simply select them all. In this case, I'll just drag a rectangle around 'em and now I can either choose file, compress five items, or alternately I can right click on any of the selected items and choose compress five items from here. Now, I also could have selected the enclosing folder, in this case the exercise files folder, and chosen to compress that instead. If I wanted the folder itself to be included. But just like that, I now have this file called Archive, which is my zip file. I'm going to drag that to my desktop. And now I have the single file to attach to an email that's a little smaller in size than the original collection of documents. So when you compress your files, you're not doing anything to the original files. Those five items are still sitting uncompressed on my computer right here. I just have a copy of them compressed sitting on my desktop, currently named Archive.zip. At this point I usually like to rename the file into something a little less generic. So I'll click its file name and I'm going to call this ex files.zip. But that's pretty much it for knowing how to compress files. Now, how does compression work? To explain it in very basic terms, compression programs examine the contents of a file and try to locate redundant information which you can then use as kind of a short-hand to compress. For example, let me open up text editor here. And let's say I wanted to send a file that contains this series of characters. Now, a compression program might look at this and say, okay there are four As in a row. So it would write 4A. There are for Is in a row, so I'll type 4I. And there are one, two, three, four, five, six Es, so 6E. So instead of writing all of these characters, it would write four A, four one, six E which is much shorter than spelling the whole thing out. Now, when it comes time for the rezipping of this file to decompress it, their compression program will look at the short-hand and then expand it out to the full version. Now, this is a highly simplified explanation of how compression works but I think it's a fair representation. So what happens when you receive a compressed file? Well again, the Mac requires no additional software to expand or unpack a zip file. So let's say I just received this file called ex files.zip and I have it copied to my desktop. To unzip or unpack it, I just double-click it. And just like that, the collection of files is unpacked, I have this folder called ex files now and I can look inside to find my individual documents. Now at this point, I could throw away the zip file or I could just save it in case I want to keep a compressed version of these files around. So, it's super easy to zip and unzip files on a Mac. And it's not that difficult to do on Windows, either. So if you're sending a zip file to Windows users, they'll be able to unpack your files as well. I highly recommend you always zip any files you intend to send over the internet. You might not see a significant file size saving for smaller files, but it can make a big difference for a larger collection of files.

Contents