Rephrase shells (#205)

The previous version was suggesting the usage of getent, which bares the
risk of users being able to access personal data they should not see.
(although, this still being the case, we maybe don't want to advertise
such commands publicly)

Furthermore, the warning against changing the default shell was
rephrased.

---------

Co-authored-by: Ben Cumming <[email protected]>
Co-authored-by: Mikael Simberg <[email protected]>

Author: 3 people

docs/guides/terminal.md

@@ -8,26 +8,24 @@ This documentation is a collection of guides, hints, and tips for setting up you
 
 Every user has a shell that will be used when they log in, with [bash](https://www.gnu.org/software/bash/) as the default shell for new users at CSCS.
 
-At CSCS the vast majority of users stick with the default `bash`: at the time of writing, of over 1000 users on Daint, over 99% were using bash.
-
 !!! example "Which shell am I using?"
 
     Run the following command after logging in:
 
     ```console
-    $ getent passwd | grep $USER
-    bcumming:*:22008:1000:Benjamin Cumming, CSCS:/users/bcumming:/usr/local/bin/bash
+    $ echo $SHELL
+    /usr/local/bin/bash
     ```
 
-    The last entry in the output points to the shell of the user, in this case `/usr/local/bin/bash`.
-
 !!! tip
     If you would like to change your shell, for example to [zsh](https://www.zsh.org), you have to open a [service desk](https://jira.cscs.ch/plugins/servlet/desk) ticket to request the change. You can't make the change yourself.
 
 
 !!! warning
-    Because `bash` is used by all CSCS staff and the overwhelming majority of users, it is the best tested, and safest default.
-
+    If you are comfortable with another shell (like Zsh or Fish), you are welcome to switch.
+    Just keep in mind that some tools and instructions might not work the same way outside of `bash`.
+    Since our support and documentation are based on the default setup, using a different shell might make it harder to follow along or get help.
+    
     We strongly recommend against using cshell - tools like uenv are not tested against it.
 
 [](){#ref-guides-terminal-arch}