Hello,
It looks to me that I'm completely lost in this
I have Raspberry Pi running Raspbian. I installed Media server Plex on it.
My movies are located on MacBook (same LAN). Hence I have to configure Plex and point for storage on Mac.
I installed netatalk on Pi. I am able to access Mac but only when I provide afp://<Mac location>. Plex does not take it. It wants only absolute path to folder. Then I installed samba but likely did not configure it properly and it does not give me path to Mac either.
Could someone please provide me instructions how to access folder on Mac from Linux using absolute path to it?
Thanks in advance.

I've have not played with plex yet but I believe you need to mount the remote share and use the local mount point. Basic syntax for both commands:

mount -t cifs //mac/share /mnt/share
or
mount_afp -o user=U,group=fuse afp://USER:PASSWD@mac/FOLDER /mnt/share

It would be a good idea to mount the drive as say a share that continues to be owned and operated by the Mac.

Thanks for suggestions but I still need some more help with it.
I did this:
login to RPi.
mkdir /mnt/plex
On Mac:
hostname -> I-MacBook.local
user -> I
group -> staff
On RPi:
user -> pi
sudo mount -t hfs /Users/I/Movies/Completed /mnt/plex
mount: special device /Users/I/Movies/Completed does not exist
**
sudo mount -t hfs I-MacBook.local@/Users/I/Movies/Completed /mnt/plex
mount: special device IMacBook.local@/Users/I/Movies/Completed does not exist
**
On Mac:
mount_afp -o user=I,group=staff afp://piassword@/Users/I/Movies/Completed" /mnt/plex
**
On RPi .. when I go to network I could access my MacBook like this:
afp://I-MacBook.local:548/
Could you please help me with syntax and understanding how to mount my MacBook IMacBook.local to RPi?

Thanks

There are local filesystem types i.e. ext4,hfs,xfs etc for hard drives attached to the computer and there are remote/network filesystem types like nfs,cifs etc to access files on another computer on the LAN. To access a remote computer you need to use a network filesystem type.

To mount a remote filesystem you need to run the command on the client which is the Pi to access the server which is the Mac. I assume you are entering the afp://I-Macbook.. in the filesystem browser. The browser uses a virtual filesystem and depending on version it may or may be accessible in a terminal. I don't run a desktop on my Pi.

mount_afp is a fuse command line utility to mount a Mac afp network share. cifs is for mounting a samba share. I rarely use a Mac so I have never tried sharing using afp. The samba server on the Mac needs to be running and configured for the directory that you want to share.

Both commands are to be run on the Pi.

You can probably do it all from the graphic interface for which the Mac is so justifiably famous. Macs support a wide variety of networking protocols and simply call it, "sharing."

SMB (Windows) and AFP are supported most easily. Since Macs are fundamentally Unix machines, NFS is also supported, and there's a very nice NFS Manager application out there (for about $20 per seat) that is well worth it, unless you like monkeying-around with configuration files.

There's also WebDAV support.

first "macbook on same lan" doesn't tell us something IMPORTANT. is the storage drive USB on a hub connected to both computers? or are you ssh'ed (telnet) into the mac ? or are you trying to use a (new mount hack) that mounts drives over lan offered by something the mac supports ? or trying to use something in macbook pro settings that says it shares drives with (old? new?) version microsoft computers?

also what macbook? these are released OVER DECADES - the linux support needed depending on which macbook would be radically different

i have no idea what mount in (ie newest ubuntu release) can do with or without plex, but i know the "newer apple FS" is not supported hardly in linux that is a few years older (have no idea if they fixed it)

is there a chance you can just scp(1) the movie from the mac to /tmp on the raspberry and then view it from /tmp ? or use ssh to make a socket of the file transfer and give your app the /path to the socket file ?