Running 2 and more Skype instances on Mac OS X simultaneously

What follows is a copy-paste of this Skype forum post. I’ve tested this on 10.8.2. Seems to work.


We do not officially support or recommend running two instances of Skype simultaneously on the one computer. However, it is possible to do this:

Make a copy of Skype:

  1. Open Finder.
  2. In the sidebar, click Macintosh HD > Applications.
  3. Click Skype to select it.
  4. Press Cmd+C, then Cmd+V to copy and paste Skype.
  5. Skype copy appears.

Change the bundle identifier in the Info.plist file:

  1. Right-click the copy of Skype and select Show Package Contents.
  2. Click the folder named Contents, then open the Info.plist file.
  3. In the Info.plist file, locate the bundle identifier setting, and change it to (for example:
  4. Go to File > Save, and then close the file.

Change the data path used by Skype for storing data files:

  1. Open Terminal (Go to Finder and in the Search field, enter Terminal).
  2. In the Terminal window, enter the command:
    defaults write <new bundle identifier > DataPath <”path to a new data directory”>
    For example:
    defaults write DataPath “~/Library/Application\ Support/Skype\ copy”

Note: after Microsoft had terminated support for older versions and forced everyone to update their Skype this step returns an error now:

2014-08-23 11:13:58.912 defaults[45773:707]
Rep argument is not a dictionary
Defaults have not been changed.

However, I just ignored it and started up Skype and it worked. I can still run two copies of Skype as before.

  1. Press Return.


You can rename Skype copy to anything you’d like it to be. For example, you could use Skype business instead. This comes in handy, because when placed on a dock a tooltip will display this Skype business name and make easy for you to distinguish which Skype dock icon represents what instance.

Writeable Linux NFS 4 shares and Mac OS X Finder

In my setup I run Arch Linux and NFSv4 server on this system. I’d like to connect to any of the shares thatare available on this laptop server and write to them from the Finder in Mac OS X.

NFS Configuration

First things first, the Arch Wiki:

Then you get NFS and its dependencies installed.

Now, NFS configuration.

I export just one folder, /srv/nfs4/seagate1TB. NFS4 has the concept of the root for the exports and that’s what /srv/nfs4/ is exactly. Access is granted exclusively to specific /29 network.



I encourage to read ‘man exports’, specifically General Options, User ID Mapping and EXAMPLE sections.

After reading ‘man exports’ it was clear that the key to configuring writeable NFS share were all_squash, anonuid and anonguid options.

In plain English, when Finder copies to NFS share/export files and folders they have to be created on the NFS server. The server then has to decide who these files are going to belong to. Since the server has no way to tell what user (user ids, the UID and GID) are currently used on the client OS X machine, and also because it is, in fact, not always desired that files are created on a server with the same UID/GID of the user that runs NFS client software, there are basically two options.

First, is to use all_squash which is going to ‘anonymize’ UID/GID and instruct NFS server to create files in such a way that they belong to nobody user. Alternatively, you can set all_squash, as well as anonuid=1000 and anongid=1000 to match first non-system user on a modern Linux system.

So, I know that I store files on the disk that is exported as a specific user, so I configured my NFS export/share to create files on behalf of a client (Finder in Mac OS X) as that specific user (that’s what anonuid and anongid are for).

One more thing. Just for the sake of completeness, this is how I mount the disk and make it available for NFS export:


UUID=9d244934-d9fa-4a8e-8dd7-5c595f5518cf /mnt/seagate1TB auto defaults 0 0

# NFSv4
/mnt/seagate1TB /srv/nfs4/seagate1TB none bind 0 0

I first mount this disk device with unique identifier (UUID) in /mnt/seagate1TB, then bind it to /srv/nfs4/seagate1TB. I like to keep things multihomed sort of. Meaning, they can do many functions simultaneously, so this disk isn’t used for NFS alone and it makes sense to mount it in /mnt/seagate1TB first.

If you couldn’t care less about such things, just mount it directly to /srv/nfs4/seagate1TB to have it as a reminder that it is explicitly used for NFS.

You can also use symlinks, that are really handy. Consider the following example:

% ls -l /srv/nfs4/

disk -> /run/media/joe/disk
disk-1 -> /run/media/joe/disk-1
disk-2 -> /run/media/joe/disk-2
seagate1TB -> /run/media/joe/9d244934-d9fa-4a8e-8dd7-5c595f5518cf/

In fact, I’ve switched to using symlink because it lets me maintain NFS export handles in a consistent fashion regardless of where the actual filesystems/disks are mounted. So, I can always access them as:

while the disk are mounted elsewhere.

Firewall and NFS4

If you have a restrictive firewall things get really interesting. rpcbind daemon uses random ports to facilitate client to server connections. Fun! Honestly, I don’t know how to deal with this. Well, except restarting firewall manually or granting access to all destination ports for the host in question (this is what I’m doing on my home LAN).


To quickly unexport all shares on the server:

exportfs -au

To quickly mount/export all shares on the server:

exportfs -rav

-v will increase verbosity so that you know what’s going on.

How to release mouse pointer in virt-manager running inside VNC client on Mac OS X

My setup consists of Mac OS X system that runs RealVNC client to connect to Ubuntu Server machine that is a KVM host via VNC.

When working in guest VM graphical console (as opposed to text console which usually requires additional configuration of guest VM) you may end up clicking into the black area.

That would grab your mouse pointer.

Actually, you don’t have to click VM screen area if all you want to do is type in something but if you must use mouse to click something inside the terminal view it’s going to get locked.

To release your mouse pointer normally you’d press Ctrl_L+Alt_L, as it is stated in the window title.

Screen Shot 2013-01-31 at 5.18.48 PM

However, it didn’t work on Mac.

Instead you need to use:


which has the same effect.

PS: interestingly it is one of the top blog posts on this blog. I guess way too many people run into this problem? If you’re one of them let me know in the comments section down below.

Mac OS X writes too much data to disk, or does it?

This is just an observation I made a couple of days ago. I had my new Macbook Air 11″ on for some 13hrs during which all I did was light use of Google Chrome to look up things once in a while, chat with people in Skype and Adium, listen to radio streams in iTunes, work in a terminal, of course, had running which is configured not to save anything to disk, and by the end of the day Activity Monitor reported some 5GB worth of disk writes. 5 gigs, really?

Why would I be concerned? Well, I’m generally speaking curious, but also there’s a legitimate concern because SSD drives, which are of MLC type in Macbook Air’s, on average are guaranteed to last 5 years with average 40GB disk writes per day. So, you can see that 5GBs per day in that context isn’t really a small number.

So, I set out to figure out to see distribution of those disk writes but I haven’t found a solution yet. dtrace looks like the tool that could pull out this data but it falls short of showing accumulated values over time. What I’m talking about is Linux equivalent of iotop -o -a, which is just amazing, simple and user-friendly compared to dtrace.

Which reminds me to say that Mac OS X is a funny OS. It makes it really easy to use a computer in GUI department, but Apple seems to have applied their philosophy of radically simplifying things to command line applications as well. Less of output (otherwise useful and detailed) seems to be characteristic of Apple’s version of such tools as iotop and sar, to name a few.

This I find a little frustrating and limiting. By and large, though, I really like Mac OS X and the whole experience of running Macbook Air.

I’d highly recommend it.

Gets Mac OS X

Gets Mac OS X and spends most of the time working in Terminal anyway

I work on a mid 2012 Macbook Air 11″ these days.

The specs:
2.0GHz Intel Dual­Core Core i7, Turbo Boost up to 3.2GHz
128GB Flash Storage

Love the Mac OS X. However, ironically coming from the Linux world I’m irresistibly drawn to Terminal application and find myself poking around a lot. After all that’s exactly how I see Mac OS X, a stable, beautiful, thought-out DE. Underneath all the beauty, bells and whistles, fancy features, there’s UNIX. Do I really have to say more? My friends are worried that I’m lost to Linux community but that’s not really true. Not a bit. I still have my Arch Linux laptop running and doing those tasks that it does better than Mac OS X. I’m just sticking with UNIX philosophy of using the tools that do one thing the best. To me Mac OS X is currently doing the best job of offering a desktop environment.