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-prefetchable) [size=8K]
Capabilities: <access denied>
Kernel driver in use: iwlwifi
Kernel modules: iwlwifi
Look for correctly loading modules
$ lsmod | grep <your module>
In this case, the module is iwlwifi.
Show kernel messages related to your module
$ dmesg | grep <your module>
List hardware config for your network
$ sudo lshw -c network
Show and/or configure network interface(s)
$ ifconfig
Show and/or configure wireless interface(s)
$ iwconfig
Scan your network
$ iwlist scan
Network-manager configuration
$ nm-tool
Show switches for your wifi device
$ rfkill list all
If you want more detailed info/debug options you can run man <command> for each of them.
If you have wireless problems, post the output of these commands and we'll help you. Not all of them are necessary, but the more info the better.
For log files, check out the /var/log/ directory. The dmesg, boot and xorg.0.log files are generally the most useful ones, at least in my experience. For wifi stuff dmesg will do.
Best Answer
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:
or
or
After this general problem description, what other information is interesting depends on what sort of hardware you're having problems with, and what problems you're having.
In general:
sudo lspci -nnwill list all the PCI devices in your system. This will include all the expansion cards (Video cards, WiFi, etc) in your system, whether or not the kernel has a driver for them. This information is useful if you're not sure precisely what hardware you have.lsusbwill list all the USB devices connected to your system. Again, this is useful if you're not sure precisely what hardware you have. It's also useful to check that the device is actually plugged in correctly!/var/log/udevand/var/log/dmesgwill have information about what devices the kernel has detected. These logs are generally very big - unless you know what parts of the log are interesting it's not a good idea to include these in your question, although a link to them could be useful (you can use http://paste.ubuntu.com for large logs)sudo lshw --class Xprsudo lshw -C Xcan also give a bit of valuable hardware info on the specifed classX- examples classes includecdrom,communication,core,cpu,display,isa,medium,memory,multimedia,network,pci,scsi,serial,storageandusb- so for instance you can usesudo lshw -C networkto show info on the network cards the computer can detect.For Video problems:
/var/log/Xorg.0.logis the X server log file. This is useful for all video problems. This file can get long so feel free to just put it on http://paste.ubuntu.com. Be sure to give a link to your "paste" so we can find it when we need to.LIBGL_DEBUG=verbose glxinfowill display information about 3D acceleration support, useful for problems with 3D or desktop effects.lspci -nn | grep VGAwill list all the video cards in your system, useful if you are not sure what type of video card you have./usr/lib/nux/unity_support_test -pshould be used for compiz and other Unity compatability issues.For Audio problems:
cat /proc/asound/cardswill list the audio devices that have been detected. You should include this.cat /proc/asound/card0/codec#0will contain information about the first sound card, including information about the input/output ports connected to it. If you have a problem with plugging in a microphone, headsets, or external speakers, include this. You may also have more than one sound device. In that case, there will be more than one/proc/asound/card???directory.