A user's graphical session collapses back to the login screen a second after they authenticate. The X server itself started normally. Which file should you read first, because it collects the standard output and standard error of the programs that the user's session tried to run?
LPIC-1 Exam 102-500, objective 106. User interfaces and desktops easy
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How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.
The options
Correct ~/.xsession-errors
Correct. The session startup script redirects the session's stdout and stderr into this file in the user's home directory, so a toolkit crash, a missing binary or a failing autostart entry leaves its message there.
Not correct /var/log/Xorg.0.log
Wrong for this fault. That is the X server's own log — driver probing, screen and input device detection, EDID data. It is where you look when X will not start at all, but here X started fine.
Not correct ~/.xinitrc
Wrong. That is a script that startx runs to launch a session, not a log. It is worth reading to see what the session tries to start, but it records nothing.
Not correct /var/log/wtmp
Wrong. wtmp is a binary record of logins and logouts, read with last(1). It shows that a session began and ended, never why it ended.
Why
Split graphical faults into two layers. The server layer — drivers, modes, input devices — logs to /var/log/Xorg.0.log or, for a rootless server, to ~/.local/share/xorg/Xorg.0.log. The client layer — the desktop environment, the window manager and everything the session autostarts — writes to ~/.xsession-errors, because the session script redirects its output there. Which file has fresh timestamps tells you which layer failed.
Where this comes from
- Cited
- manual page Xsession(5)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 106 and space the ones you get wrong.
More questions on this objective
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