Difference is in units they use.
du uses BLOCKSIZE=4096 bytes by default (rounded if Human Readable format option -h i.e. df -h)
Finder uses BLOCKSIZE=1000 by default
$du -h /usr/lib/libblas.dylib
4.0K /usr/lib/libblas.dylib
and same in Finder.
regarding getting your SMB sharing connection from linux working...
Samba no more, mount.cifs needs extra options, "nounix,sec=ntlmssp"
Don't use the linux gui to connect, have bro open a terminal and try these commands
(and dig my ascii art!)
=^..^= `·.¸¸ ><((((º>.·´¯`·><((((º>
amitsbrother@linux:~$
amitsbrother@linux:~$ sudo apt-get install cifs-utils
...
amitsbrother@linux:~$ mkdir /mnt/mavericks_smb
amitsbrother@linux:~$ mount.cifs //172.17.8.212/smb_share /mnt/mavericks_smb/ -o user=amitsbrother,password=trustno1,nounix,sec=ntlmssp
amitsbrother@linux:~$
amitsbrother@linux:~$ mkdir /mnt/mavericks_smb_dup
amitsbrother@linux:~$ mount -t cifs //172.17.8.212/smb_share /mnt/mavericks_smb-dup -o username=amitsbrother,password=trustno1,nounix,sec=ntlmssp
Once this is working, you can create a script for your brother to automatically mount when it is executed from the gui. Basically, the script is just the mount point creation, and the cifs connection to the smb server... so 2 or 3 lines including the shebang.
Make sharing work now with no passwords
To make it super simple, I'd enable web sharing on the Mac, and put the files you want to share to the Linux box in a folder in ~/Sites/a_folder/ . Then give your brother the address that it tells is your personal web sharing address in the Sharing Preferences pane when you enabled Web Sharing. Tell your brother to open a browser and put in that address; it will give him a directory listing as long as there is no index.html file in there. He can download files with his browser. This is one way sharing, from the Mac to the linux box, and will work fine as long as there are no files over 4GB (unless apache fixed that issue and didn't tell me about it). I believe directory listing is enabled by default on the Mac apache2 server.
To share in the other direction, from linux to Mac, you could do the same from the Linux box:
sudo apt-get install apache2
You can enable directory listings on the Linux apache2 server with instructions here. Those instructions inadvertantly also cover how to get the apache2 server up and running. Then you need the ip address of the Linux box, and the relative location from the apache root to see the files in your Mac's browser.
This shouldn't take 5 minutes to set up 2 x 1-way sharing through browsers on both boxes, and relieves you from hacing to trouble-shoot the slightly more complex task of installing and configuring netatalk or running SMB sharing from the mac and getting the linux client to mount it, which isn't always a "it just works" situation, like running 2 apache2 servers is.
Best Answer
AS @lhf comments export/import implies that there is some information lost during one of the processes so that you can't export and then import and get exactly the same document back.
Save usually writes the file in the format that is native to the application or in the same format as the file was opened in.
Some applications e.g. Microsoft Office will not use export as much as this but use save as to allow conversion of the format of the document and possibly lose some information e.g. Excel can save as .csv. (I don't have MS Office here and can't remember if they have an export on the file menu). The do have an import that adds the selected document to the current one so another meaning.
The examples you give are both that the file file format is native to an application ( Open Office and PhotoShop) and the other applications' export converts their own format to these on export.