Kramdown supports language on the fenced code line

docs/ivanx/a2server_installubuntu.md

@@ -44,10 +44,9 @@
 
 * If you installed Debian rather than Ubuntu, type:
   
-  ~~~
+  ~~~ bash
   sudo sed -i '0,/-eq 0/s/-eq 0/-ge 0/' /etc/profile
   ~~~
-  {: .language-bash}
 
 * When you're back at the prompt, type `sudo shutdown -h now` which
   will turn off the (virtual) machine.

docs/ivanx/a2server_netboot.md

@@ -7,10 +7,9 @@ running from "bare metal" if you wanted to.
 
 To do this, [log into the a2server console](a2server_commands.md), and type:
 
-~~~
+~~~ bash
 a2server-setup
 ~~~
-{: .language-bash}
 
 After confirming that you want to proceed, you will be asked if you want to
 set up A2SERVER for network boot. Just follow the prompts. If you elect to

docs/ivanx/a2server_recovery.md

@@ -66,10 +66,9 @@ _A2SERVER on Raspberry Pi without screen/keyboard mouse, and a Linux computer_
 
 * On your Linux computer, type:
   
-  ~~~
+  ~~~ bash
   wget ivanx.com/a2server/fix; source fix
   ~~~
-  {: .language-bash}
 
 * Follow the on-screen instructions.
 
@@ -93,10 +92,9 @@ computer_
 
 * In the virtual machine window, type:
 
-  ~~~
+  ~~~ bash
   wget ivanx.com/a2server/fix;source fix
   ~~~
-  {: .language-bash}
 
 * Follow the on-screen instructions.