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multiuser [2010-02-18 20:38] 78.90.214.52 |
multiuser [2021-02-19 20:18] (current) asciiphil [Extras] typo |
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screen can allow multiple users to access the same session. This can be useful for all sorts of information sharing, from helpdesk applications to extreme programming. By default, multiuser mode is disabled, for security reasons. | screen can allow multiple users to access the same session. This can be useful for all sorts of information sharing, from helpdesk applications to extreme programming. By default, multiuser mode is disabled, for security reasons. |
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===== Basics ===== | ===== Basics ===== |
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''screen'' has a relatively flexible representation of permissions. The permissions that can be set are read, write, and execute. Read does nothing. Write applies to windows and allows the user to type into the windows. Execute applies to commands and allows the user to run the specified commands. "''#''" can be used to apply to all windows and "''?''" to all commands. | ''screen'' has a relatively flexible representation of permissions. The permissions that can be set are read, write, and execute. Read does nothing. Write applies to windows and allows the user to type into the windows. Execute applies to commands and allows the user to run the specified commands. "''#''" can be used to apply to all windows and "''?''" to all commands. |
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When experimenting with permissions, the ''[[commands:su]]'' command is sometimes useful. It allows you to change the effective user for the current display (just like the Unix ''su'' command allways you to operate as a different Unix user). | When experimenting with permissions, the ''[[commands:su]]'' command is sometimes useful. It allows you to change the effective user for the current display (just like the Unix ''su'' command allows you to operate as a different Unix user). |
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Somewhat relatedly, only one user can be typing in a given window at once. That user has the window's //writelock//. Normally, writelocks are in auto mode, meaning that whoever types into the window first gets the lock. The lock is relinquished when the user leaves that window. An acquired writelock can also be removed by using the command ''[[commands:writelock]] off''. If the user uses ''[[commands:writelock]] on'', he will keep the writelock even after leaving the window. | Somewhat relatedly, only one user can be typing in a given window at once. That user has the window's //writelock//. Normally, writelocks are in auto mode, meaning that whoever types into the window first gets the lock. The lock is relinquished when the user leaves that window. An acquired writelock can also be removed by using the command ''[[commands:writelock]] off''. If the user uses ''[[commands:writelock]] on'', he will keep the writelock even after leaving the window. |
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* You may also need to set-uid on the screen executable. Do this on your screen executable as root: ''chmod u+s /usr/bin/screen''. This is in ''[[man:start|man screen]]'' towards the end. | * You may also need to set-uid on the screen executable. Do this on your screen executable as root: ''chmod u+s /usr/bin/screen''. This is in ''[[man:start|man screen]]'' towards the end. |
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