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115

The most important information you can give is what you've done, what you expected to happen, and what you observe has happened. This question is a particularly fine example of a hardware-detection problem with a USB device. Other examples of this could be: I installed Ubuntu 10.04 Desktop on my Dell Optiwhatever 312 laptop. When I log in, my ...


70

General Alpha Information If you've been redirected here you've probably asked a question about an Alpha or Beta release of Ubuntu. Generally speaking we don't take questions about running or using unreleased versions of Ubuntu releases here since development releases change almost by the hour and usually it's broken and alpha testers are expected to give ...


44

Upstart logs your service execution in a log file by the same name in /var/log/upstart/your-service-name.log. It should be helpful.


43

Wireless Cards Wireless connectivity issues are fortunately becoming rarer with each Ubuntu release. However problems still occur. The following information will help diagnose wireless connectivity issues in questions posted on Ask Ubuntu, you can open a terminal by hitting Ctrl-Alt-T and typing in one of these commands, then edit your question to add the ...


33

In Maverick Meerkat (10.10) Ubuntu introduced a patch to disallow ptracing of non-child processes by non-root users - ie. only a process which is a parent of another process can ptrace it for normal users - whilst root can still ptrace every process. Hence why you can use gdb to attach via sudo still. You can temporarily disable this restriction (and revert ...


30

Forums If your question on Ask Ubuntu was linked to this answer then this is where you should probably go to repost your problem. The Ubuntu Forums' Development & Programming section is a good place to start. The precise subforum depends on the release, but at the moment you want the Ubuntu Development Version. Take a look through the recent ...


25

Each process in linux has a special directory /proc/{pid}/fd/. 0 is stdin, 1 is stdout and 2 is stderr. So, assuming you are only interested in diagnostic output you can determine the process pid, and then in the terminal do: to see stdout: cat /proc/{pid of process}/fd/1 to see stderr: cat /proc/{pid of process}/fd/2


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IRC (Internet Relay Chat) #ubuntu+1 on irc.freenode.net #ubuntu-bugs if helping report/triage bugs


22

Before an upgrade, always test sudo apt-get --simulate dist-upgrade If you get an error about broken packages, don't upgrade.


18

ubuntu-devel-announce mailing list When large changes are being made usually a developer will post on the ubuntu-devel-announce list. This list doesn't get many posts (compared to some of the other Ubuntu lists!) so for pre-release testers there is no excuse not be subscribed to it.


18

See https://wiki.ubuntu.com/DebuggingHardwareDetection https://wiki.ubuntu.com/DebuggingProcedures is usually a good starting point if you want to know what information is useful for a bug report.


16

Keep an eye on package uploads Uploads to the archive are sent to a mailing list, named after the animal nickname, for example lucid-changes, utopic-changes, etc. Following this list can be useful to see when risky uploads are being uploaded so you can hopefully avoid problems before it's too late. Also the Archive Status tool is useful for showing the ...


15

Behold the power of the terminal! List PCI devices / wifi network relevant portion only $ lspci -v | grep -iA 7 network 03:00.0 Network controller: Intel Corporation Centrino Wireless-N 1000 [Condor Peak] Subsystem: Intel Corporation Centrino Wireless-N 1000 BGN Flags: bus master, fast devsel, latency 0, IRQ 43 Memory at f0500000 (64-bit, ...


14

Check syslog (/var/log/syslog) for messages about config file issues. From the commandline you can run nginx -c /etc/nginx/nginx.conf -t to have nginx check your configuration for errors.


13

These might be helpful (depending on the type of hardware): dmesg lspci lsusb


10

All of the following information (and quite a lot more useful Upstart help) is from The Upstart Cookbook. Section 13 covers debugging. In this specific case of tracing a "script" stanza of an Upstart job you should add the following lines right below the word "script": exec 2>>/dev/.initramfs/myjob.log set -x The reason for the odd location is ...


10

Excellent question. Workloads The /usr/share/xdiagnose/workloads directory has a set of workloads designed to exercise your graphics system to trigger lockups. $ ls /usr/share/xdiagnose/workloads/ README do_monitor_rotation_loop do_chws_loop* do_screensaver_loop* do_cpu_spin_loop do_video_loop* ...


8

Or you can use strace like this sudo strace -p $pid_of_the_process


8

The following logs will contain details about hardware as it was seen by various system services (kernel, udev, etc) at boot time: /var/log/udev /var/log/dmesg


8

On Ubuntu versions after 10.10 you'll run into this in more related applications, such as QtCreator. It is a security feature of Ubuntu that prevent the debugger to attach to processes not owned by him. This is filed as a bug #3509 against QtCreator. To work around this issue, do this: temporary solution (won't survive a reboot): echo 0 | sudo tee ...


7

1) They contain debugging symbols. 2) If you need to debug things locally, then yes, they are necessary to get the debugging symbols. However, -dbg packages are somewhat deprecated, and you should add the ddebs archive to get the dbgsyms packages instead, when possible. 3) Not usually. If you report a crash bug, the crash reporting server will rescan with ...


7

Sometimes it's just the X server that is frozen. Try to get a console by hitting CTRL-ALT-F1. If that won't do, try logging it your machine using SSH (install openssh-server package first). If you can't get a shell, reboot. Once you have a shell, check the system logs (/var/log/syslog, /var/log/messages, /var/log/Xorg.0.log and ~/.xsession-errors). Scroll ...


7

So firstly install Flash-Aid firefox plugin, and use it to install stable version of Flash Player. Next download "Linux Flash Player 11.2 Plugin content debugger" from Adobe (it doesn't matter if you have 64-bit Ubuntu). Put the proper files in /usr but libflashplayer.so file use to overwrite /usr/lib/flashplugin-installer/libflashplayer.so . But it's not ...


6

As izx has commented, this should only be able to happen due to a kernel bug. So anyone who can currently produce this problem--including and especially the original poster of this question--would be well-advised to report it as a bug by reading that page thoroughly and carefully, and then running ubuntu-bug linux on the affected machine. This should be ...


6

You can do this in just a few steps: Get the necessary tools and build dependencies: sudo apt-get install devscripts fakeroot sudo apt-get build-dep <package> Set the build options: export DEB_BUILD_OPTIONS="debug nostrip noopt" Build the package: fakeroot apt-get source -b <package> Install the package: sudo dpkg -i <package>*.deb ...


6

You can attach with gdb to a running process. The syntax is gdb program pid Ok, you cannot see source code, if debug information are stripped, which is the default for deployed applications. But you can probably see stdout/stderr and debugger messages, segfaults.


6

There are multiple graphical frontends for gdb. GNU DDD and KGDB to mention a couple. GNU DDD: KGDB: Update: I failed to mention that gdb actually has a built in text-based user interface if you run it with gdb -tui:


5

Launchpad Answers Launchpad Answers is another official question-and-answer site for Ubuntu (and some other software that is developed on Launchpad), but whereas AskUbuntu is focused on producing reusable answers that help lots of people and evolve over time, Launchpad Answers is a support tracker focused on replying with answers to each question, whatever ...


5

Execute these following commandline tool: cat /var/log/Xorg.0.log lspci dmesg lsusb



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