OSX Linux archive question (puzzled!)

Getting my new Linux Asus Eee PC 900 ready for my upcoming trip, I want to carry a bunch of pictures on it. Memory is very limited, so I figured I'd zip the pictures. Since I've been unable to get tar to work (I cannot figure out the syntax) I just used the Mac's archive utility to zip my pictures. On the Mac I can zip and unzip them and everything looks normal.

But when I unzip the archive on the Eee, I get all my pictures, but in addition I get a subdirectory called "__MACOSX" and in that subdirectory are a bunch of files with the names of some (not all!) of my pictures, but with "._" prepended. So if one of my pictures is titled "IMG_0546.jpg" there will be a file in the __MACOSX directory named "._IMG_0546.jpg"

Not all of my original files are mirrored this way, but all the mirrored files have names built from names of my pictures. Ie, there are fewer files in the subdirectory than in the main one.

I tried copying the pictures to a different directory and zipping them from there, but the result was the same.

I solved the problem by just copying the pictures themselves over to the Eee and using the Eee's own zip utility (which was easier to figure out than tar). But I'm very curious about what are all these files on my Mac that don't show up there, but do show up when an archive is opened on the Linux box.

 

Then why are only some of the actual pictures represented in the mirrored file names?

And why, when I specifically select a list of files for inclusion in a zip file, does the archiving program include a bunch of other files, which I had not selected, in the archive?

Having no tools available that I know of for deleting files in an archive, I ended up having to do it the long way: copying the pictures over to the Linux box via a usb memory stick, and archiving them there (once I found a program I was able to do that with.)

 

Thanks for that info. I agree with the author that it's bad for it to be doing that. But at least I understand what's going on, and I know that I have to use zip from a terminal rather than the context menu from the finder, to make a clean archive. Or, as I did end up doing, make the archive on the Linux box.

 

For some reason, I get nothing but error messages when I try to create an archive with tar. The man pages are very cryptic. And even your example above does not say which is the input and which is the output.

Is it

Code:

tar cvfz archive.tar.gz <input files> <output archive>

or is it

Code:

tar cvfz archive.tar.gz <output archive> <input files>

I have no problem extracting files from an archive with tar.

However, my linux box has zip and unzip, which work for me. So I really don't have a problem. (BTW, between tar and zip, which produces the better compaction?) It's just that it would have been easier to create the archive on the Mac and move the archive, rather than having to move all the pictures, and then archive (to save space) on the linux box. It was really mostly a matter of curiosity for me why those added files and directory were being created.

And then rmdir was refusing to work because there were files in the __MACOSX directory, and it took me a while to figure out that "rm -r" will empty and remove a directory in one shot. (It's been many years since I ran Unix on my 80286!)

And since I didn't know what was going on, I didn't think of opening a terminal on the Mac and using tar or zip from there. I never do that on the Mac so it didn't occur to me until I didn't need it any more because I'd already done it the "long" way.

 

Thanks everyone for all the clarifications. I'll give tar another try just to see if I understand it now.

I don't know if I'd want to reduce the resolution of the pics, because someone might want copies, and I'd rather give them the full pics. I thought I was saving space by archiving them, but now that I understand I'm not, I'll probably just stick them in a convenient directory. Maybe I'll just carry them on an SD card so they don't take up space in the computer's small solid-state "HD."

The computer has a card reader, so I can use a memory card, which looks like a removable drive.

Though memory space shouldn't be a problem. Out of 4 gigs total, I have half a gig free, and I've now got all the software I need on the machine. I upgraded to Firefox 3 (not a trivial task on this box) and I got Shredder Chess, and it came with OpenOffice and some games (solitaire, Penguin Racer, Tux Draw, and a few others). Tux Draw is a drawing program for children, with a lot of useless but silly/fun tools.