Hot answers tagged


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 ...


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.


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 ...


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.


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 ...


Note: If you have a wired connection consider running the all in one wireless script outlined in this answer, it does all the heavy lifting for you! 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 ...


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 ...


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 ...


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


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


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


See is usually a good starting point if you want to know what information is useful for a bug report.


Run this command you can find problem. sudo nginx -t


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.


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, non-...


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 ...


There several different ways, i.e.: Run your script with the -x option bash -x Add set -x in a new line at the beginning of your scriptfile after the Shebang #!/bin/bash and before the beginning of your script, set -v would display the shell input lines, set -x displays the executed commands and arguments replace the shebang of your script ...


This is the intelligent input bus - is an input method framework for multilingual input. If you don't use any different keyboard layouts for ex. japanese /asian etc. Try to disable it in System Setting -> Language (something like input method from ibus to none) Try to killall ibus-daemon and tell us if cpu is still has a high load.


Yes there is Bash Debugger Project. You can also use set -x and set-v at execution. HERE and HERE or HERE is some info on that. good luck!


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


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 /proc/...


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


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 ...


(@Jamie Pate pointed this out already, but it should stand out more since this question comes up high in Google search.) Another reason to get the error: attach: ptrace(PTRACE_ATTACH, ...): Operation not permitted is because the process has already been attached to with gdb, strace or similar. To check if this is the case, run: grep TracerPid /proc/$...


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* ...


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


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


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 ...


Indeed, as @zongfu pointed out, find does not cache its results in a file, but rather the kernel is caching the directories find is reading so they can be read again without touching the disk, which is why it is faster. If you still want to see what kind of IO a program is doing though, you can use strace. This program runs another program you specify and ...

Only top voted, non community-wiki answers of a minimum length are eligible