screen
Start Screen services
Syntax:
screen [-a]
[-c filename]
[-u user_info]
Runs on:
QNX OS
Options:
- -a
- Run screen in headless mode. This option allows screen to only run virtual displays, bypassing any physical displays.
- -c filename
-
Specify filename as the absolute pathname to the configuration file that screen will use. For example:
$ screen -c /usr/lib/graphics/platform/graphics.conf
where platform is the name of your target's platform (e.g., imx6x).
Note:You must specify this -c option. Otherwise, screen won't run.
On your target, all libraries that you specify in the khronos section of your configuration file should reside in the same directory as the configuration file itself.
- -u user_info
-
Switch to the specified user after initialization where user_info can take one of the following
forms:
- uid:gid,sgid1,sgid2,sgid3,...
- All IDs must be numbers. The UID and GID are separated by a colon. The GID can be followed by a comma-separated list of supplementary group IDs. GID and supplementary GIDs are optional.
- username,sgid1,sgid2,sgid3,...
- The username must be a valid username defined in /etc/passwd; otherwise, the function errors out with EINVAL. The supplementary GIDs are optional and must be a comma-separated list of numbers. The GID is looked up in /etc/passwd. The supplementary GIDs returned are a union of supplementary GIDs (located in /etc/group for the given username) and the GIDs parsed from user_info.
screen does not drop its root privilege until the
drop_privileges
string is written to /dev/screen/command. This option sets the user that Screen will switch to after root privileges are dropped. Running the drop_privileges command completes screen's initialization, all required modules are loaded and screen transitions to running as the specified user. Running as a general user provides a more secure runtime environment. If there are any unpredictable applications on the system, they won't be able to leverage screen to run undesirable code as a privileged user.
Description:
Run the screen binary from command line to start Screen services. To run screen on your target, run screen from a shell.
Examples:
screen -c /usr/lib/graphics/<platform>/graphics.conf
joe
when the drop_privileges
command is executed:
screen -c /usr/lib/graphics/<platform>/graphics.conf -u joe
User joe
needs to be a valid username or screen will fail.