Get display number

docs.it4i/general/accessing-the-clusters/graphical-user-interface/vnc.md

@@ -30,9 +30,9 @@ You should start by **choosing your display number**.
 To choose free one, you should check currently occupied display numbers - list them using command:
 
 ```console
-[username@login2 ~]$ ps aux | grep Xvnc
-username    5971 0.0 0.0 201072 92564 ?        SN   Sep22   4:19 /usr/bin/Xvnc :79 -desktop login2:79 (username) -auth /home/vop999/.Xauthority -geometry 1024x768 -rfbwait 30000 -rfbauth /home/username/.vnc/passwd -rfbport 5979 -fp catalogue:/etc/X11/fontpath.d -pn
-username    10296 0.0 0.0 131772 21076 pts/29   SN   13:01   0:01 /usr/bin/Xvnc :60 -desktop login2:61 (username) -auth /home/vop999/.Xauthority -geometry 1600x900 -depth 16 -rfbwait 30000 -rfbauth /home/vop999/.vnc/passwd -rfbport 5960 -fp catalogue:/etc/X11/fontpath.d -pn
+[username@login2 ~]$ ps aux | grep Xvnc | sed -rn 's/(\s) .*Xvnc (\:[0-9]+) .*/\1 \2/p'
+username :61
+username :102
 .....
 ```
 
@@ -69,13 +69,14 @@ X DISPLAY #     PROCESS ID
 Another way to check it:
 
 ```console
-[username@login2 .vnc]$  ps aux | grep Xvnc
+[username@login2 .vnc]$  ps aux | grep Xvnc | sed -rn 's/(\s) .*Xvnc (\:[0-9]+) .*/\1 \2/p'
 
-username    10296 0.0 0.0 131772 21076 pts/29   SN   13:01   0:01 /usr/bin/Xvnc :61 -desktop login2:61 (username) -auth /home/vop999/.Xauthority -geometry 1600x900 -depth 16 -rfbwait 30000 -rfbauth /home/username/.vnc/passwd -rfbport 5961 -fp catalogue:/etc/X11/fontpath.d -pn
+username :61
+username :102
 ```
 
 !!! note
-    The VNC server runs on port 59xx, where xx is the display number. So, you get your port number simply as 5900 + display number, in our example 5900 + 61 = 5961. **Please, calculate your own port number and use it instead of 5961 from examples below!**
+    The VNC server runs on port 59xx, where xx is the display number. So, you get your port number simply as 5900 + display number, in our example 5900 + 61 = 5961. Another example for display number 102 is calculation of TCP port 5900 + 102 = 6002. **Please, calculate your own port number and use it instead of 5961 from examples below!**
 
 To access the VNC server you have to create a tunnel between the login node using TCP port 5961 and your machine using a free TCP port (for simplicity the very same) in next step. See examples for [Linux/Mac OS](#linuxmac-os-example-of-creating-a-tunnel) and [Windows](#windows-example-of-creating-a-tunnel).