other:x_conf
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other:x_conf [2022/08/09 15:19] jypeter [On a Windows computer with WSL+Linux and an X server installed] |
other:x_conf [2022/08/12 12:40] jypeter [Installing XQuartz] Added some tech ref |
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| ====== Installing and configuring an X server ====== | ====== Installing and configuring an X server ====== | ||
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| + | <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? ===== | ===== What is an X server? ===== | ||
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| * 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 | * 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? ===== | ===== What do we mean exactly with Local and Remote computers? ===== | ||
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| * The **remote computer or server** is another computer that you also want to interact with (using the screen+mouse+keyboard of your local computer) | * 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//** | * We only consider on this page the case of a **remote //Linux// machine** that **requires a local running //X server//** | ||
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| </WRAP> | </WRAP> | ||
| + | The ''XQuartz'' //X server// will be automatically started, if a graphical application needs it! | ||
| + | |||
| + | Check the [[https://support.apple.com/guide/terminal/script-management-with-launchd-apdc6c1077b-5d5d-4d35-9c19-60f2397b2369/mac|launchd documentation]] if you need more details | ||
| + | <code>$ launchctl list | grep quartz | ||
| + | - 0 org.xquartz.startx</code> | ||
| ===== Configuration on the remote Linux server ===== | ===== Configuration on the remote Linux server ===== | ||
| Line 124: | Line 138: | ||
| The idea is to: | The idea is to: | ||
| - | * Open a terminal and check that the ''DISPLAY'' environment variable is correctly defined on the local machine | + | * Open a terminal and check that the ''DISPLAY'' environment variable is defined on the local machine |
| * If we use [[other:win10wsl|WSL]], we also check that we can start an application using graphics in ''WSL'' | * If we use [[other:win10wsl|WSL]], we also check that we can start an application using graphics in ''WSL'' | ||
| * Connect to the remote machine | * Connect to the remote machine | ||
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| * ''xterm &'': the **recommended test application**. It will open a new terminal on the remote machine | * ''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) | * ''xeyes &'', ''xclock &'', ''gvim &'', ''gedit &'', ''eog &'', ''evince &'', ... : other //standard// applications, that may be installed (or not) | ||
| - | ==== On a Linux computer ==== | ||
| - | Some basic commands in a terminal | + | The test may fail, due to the [[other:x_conf#nothing_works|usually expected errors]] |
| + | ==== On a Linux computer or a Mac ==== | ||
| + | |||
| + | Open a //terminal// ([[other:ssh#a_recommended_terminal_for_mac|terminal on a Mac]]) and use some basic commands to check things | ||
| <code>[Local] $ hostname | <code>[Local] $ hostname | ||
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| [Remote] $ xterm &</code> | [Remote] $ xterm &</code> | ||
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| ===== Troubleshooting ===== | ===== Troubleshooting ===== | ||
| + | |||
| ==== Nothing works! ==== | ==== Nothing works! ==== | ||
| That's unfortunate, but: | 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 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 ? | * 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 | If the ''DISPLAY'' **variable is not defined (correctly)**, you will get a ''Can't open display: //[NO VALUE DISPLAYED HERE]//'' error | ||
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| $ echo $DISPLAY | $ echo $DISPLAY | ||
| + | $ setenv DISPLAY CRAP_DISPLAY | ||
| + | $ xterm | ||
| + | xterm: Xt error: Can't open display: CRAP_DISPLAY | ||
| </code> | </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'' | 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 ==== | ==== OpenGL related settings ==== | ||
other/x_conf.txt · Last modified: 2023/06/30 08:20 by jypeter
