Differences

This shows you the differences between two versions of the page.

--- other:x_conf [2022/08/09 17:14] – [On a Linux computer] jypeter
+++ other:x_conf [2022/08/11 09:47] – [What do we mean exactly with Local and Remote computers?] Examples of Linux servers jypeter
@@ Line 1: / Line 1: @@
 ====== Installing and configuring an X server ======
+<WRAP center round tip 60%>
+This detailed and easy-to-understand page will help you **set up things correctly on your own**, and help you **understand what you are doing**
+Or you can ask somebody to quickly configure everything for you, and keep on believing that things work by magic...
+</WRAP>
 ===== What is an X server? =====
@@ Line 7: / Line 15: @@
   * An //X server// **is** basically a program running on your **local** computer that understands the [[https://en.wikipedia.org/wiki/X_Window_System_core_protocol|X Windows System protocol]] used by **Linux computers** (**local** computer, or **remote** Linux servers) to generate graphics, and that can //render// (i.e. display) the graphics generated **remotely** on your **local** computer
+  * This page will mention a //''DISPLAY'' variable// several times: the X server needs this in order to know **where to display the graphics**!
 ===== What do we mean exactly with Local and Remote computers? =====
@@ Line 16: / Line 24: @@
   * The **remote computer or server** is another computer that you also want to interact with (using the screen+mouse+keyboard of your local computer)
+    * [[other:ssh#connecting_to_servers_commonly_used_by_lsce_users|Some servers used by LSCE users]]
     * We only consider on this page the case of a **remote //Linux// machine** that **requires a local running //X server//**
@@ Line 137: / Line 146: @@
   * ''xterm &'': the **recommended test application**. It will open a new terminal on the remote machine
   * ''xeyes &'', ''xclock &'', ''gvim &'', ''gedit &'', ''eog &'', ''evince &'', ... : other //standard// applications, that may be installed (or not)
+The test may fail, due to the [[other:x_conf#nothing_works|usually expected errors]]
 ==== On a Linux computer ====
@@ Line 160: / Line 171: @@
 ==== On a Windows computer with only an X server installed ====
-We just open a ''Powershell'' window (''Start'' => ''Windows Powershell'' => ''Windows Powershell'') and type some basic commands
+We just open a ''Powershell'' window (''Start'' => ''Windows Powershell'' => ''Windows Powershell'') and type some basic commands, including the creation of a ''DISPLAY'' variable
 <code>PS C:\> $env:computername
@@ Line 180: / Line 191: @@
 localhost:19.0
-[Remote] $ xterm</code>
+[Remote] $ xterm &</code>
@@ Line 194: / Line 205: @@
 localhost:19.0
-[Remote] $ xterm</code>
+[Remote] $ xterm &</code>
 ==== On a Windows computer with WSL+Linux and an X server installed ====
-We assume that [[other:win10wsl|WSL+Ubuntu]] is installed and that the ''DISPLAY'' variable is [[other:x_conf#if_you_are_using_wsl|configured correctly]]
+We assume that [[other:win10wsl|WSL+Ubuntu]] is installed and that the ''DISPLAY'' variable is [[other:x_conf#if_you_are_using_windows_subsystem_for_linux|configured correctly]]
-Open a WSL terminal (you should know how, if you have installed WSL) and type some basic commands
+Open a //WSL// terminal (you should know how, if you have installed //WSL//) and type some basic commands
 <code>[Local WSL] $ hostname
 name_of_your_local_machine
 [Local WSL] $ echo $DISPLAY
 localhost:0.0
-[Local WSL] $ xterm
+[Local WSL] $ xterm &
 [Local WSL] $ ssh -X some_login@some_remote_server
@@ Line 214: / Line 227: @@
 [Remote] $ echo $DISPLAY
 localhost:22.0
-[Remote] $ xterm</code>
+[Remote] $ xterm &</code>
+==== On a Mac ====
+FIXME
 ===== Troubleshooting =====
 ==== Nothing works! ====
 That's unfortunate, but:
-  * Have you turned on your computer?
+  * Have you turned on your computer? :-P
-  * Do you have network access, and an account on a remote server?
+  * Do you have network access, and an account on a remote server? :-?
   * Have you run the [[other:x_conf#testing|Tests]]?
-  * Have you installed and configured the //X server// correctly? Is it really running?
+  * Have you [[other:x_conf|installed and configured the X server]] correctly? Is it really running?
   * Have you configured [[other:putty_conf|PuTTY]] and/or other required applications correctly ?
-  * Is the ''DISPLAY'' variable defined correctly on the local and remote computer?
+  * Is the [[other:x_conf#what_is_an_x_server|DISPLAY variable]] defined correctly on the local and remote computer?
-=== When DISPLAY is not defined correctly ===
+==== Error when there is no X server running ====
+If the ''DISPLAY'' variable is defined, but there is **no X server**, you will get a ''Can't open display: localhost://[SOME VALUE]//'' error\\ <code>$ xterm &
+xterm: Xt error: Can't open display: localhost:23.0</code>
+Time to [[other:x_conf|read this page again]]...
+==== Error when DISPLAY is not defined correctly ====
 If the ''DISPLAY'' **variable is not defined (correctly)**, you will get a ''Can't open display: //[NO VALUE DISPLAYED HERE]//'' error
@@ Line 236: / Line 267: @@
 $ echo $DISPLAY
+$ setenv DISPLAY CRAP_DISPLAY
+$ xterm
+xterm: Xt error: Can't open display: CRAP_DISPLAY
 </code>
 Make sure that you are using ''ssh -X'' or ''ssh -Y'', or that [[other:putty_conf#changing_some_useful_settings|PuTTY is configured]] with ''Enable X11 forwarding''
-=== When there is no X server running ===
-If the ''DISPLAY'' variable is defined, but there is **no X server**, you will get a ''Can't open display: localhost://[SOME VALUE]//'' error\\ <code>$ xterm &
+==== Can't start a graphical application by clicking on its desktop shortcut ====
-$ connect localhost port 6000: Connection refused
-xterm: Xt error: Can't open display: localhost:12.0</code>
+Check the shortcut and run the command directly in a terminal to check the error message
+There is a good chance that [[other:x_conf#error_when_there_is_no_x_server_running|you have forgotten to start the X server!]]
-Time to [[other:x_conf|read this page again]]...
 ==== OpenGL related settings ====