Merge branch 'x11-mac' into 'master'

Fix OS X instructions and increase header sizes.

See merge request !119

content/guides/running_applications/how_to_setup_x11_forwarding.md

@@ -4,7 +4,7 @@ description = "Use X11 forwarding to view GUI programs remotely"
 weight = "35"
 +++
 
-##### If you are connecting to HCC clusters via a PC running Windows, please take the following steps to setup X11 forwarding.
+### If you are connecting to HCC clusters via a PC running Windows, please take the following steps to setup X11 forwarding.
 
 1.  Download Xming to your local PC and install. Download
     link: https://downloads.sourceforge.net/project/xming/Xming/6.9.0.31/Xming-6-9-0-31-setup.exe
@@ -21,9 +21,7 @@ weight = "35"
 6.  Close the xeyes application by "Ctrl + c" from the terminal or click
     the close button on the up-right corner of the graphical window.
 
- 
-
-##### If you are connecting to HCC clusters via a Macintosh, please take the following steps to setup X11 forwarding.
+### If you are connecting to HCC clusters via a Macintosh, please take the following steps to setup X11 forwarding.
 
 - Check the OS version on your Mac, if it's below 10.8., you can simply type `ssh -Y username@hostname` in your terminal to login.
 
@@ -39,7 +37,7 @@ weight = "35"
     click the close button on the up-left corner of the graphical
     window.  
       
-##### If you are connecting to HCC clusters via a Linux laptop, please take the following steps to setup X11 forwarding.
+### If you are connecting to HCC clusters via a Linux laptop, please take the following steps to setup X11 forwarding.
 
 1.  Open the remote client terminal.
 2.  Type `ssh -Y username@hostname`" in your terminal to login.
@@ -48,7 +46,7 @@ weight = "35"
 4.  Close the xeyes application by "Ctrl + c" from the terminal or click
     the close button on the up-right corner of the graphical window.
 
-#### Special note about Indirect GLX
+### Special note about Indirect GLX
 
 If you are using OS X or Linux, you may need to re-enable indirect GLX (IGLX) in order for
 the GUI application to run properly. IGLX was disabled for security reasons starting with
@@ -57,17 +55,19 @@ change is available at [this link](https://www.phoronix.com/scan.php?page=news_i
 
 To re-enable IGLX, use the follwing instructions:
 
-##### OS X
+#### OS X
 
 Open a terminal on your Mac, and run the following command:
 
 {{% panel theme="info" header="Enable ILGX on OS X" %}}
 {{< highlight bash >}}
-$ defaults write org.macosforge.xquartz.X11 enable_iglx -bool true
+$ sudo defaults write org.macosforge.xquartz.X11 enable_iglx -bool true
 {{< /highlight >}}
 {{% /panel %}}
 
-##### Linux
+Log out or restart your Mac for the changes to take effect.
+
+#### Linux
 
 You will need to create a small Xorg configuration file.  This requires `root` access, so
 run commands with care.