The following article deals with basic troubleshooting commands in terminal on an Ubuntu operating system.
The most common ways of opening a Terminal window in Ubuntu Linux are:
terminal, command, or prompt and it brings up the Terminal window as a search result.See the following article if you are looking for a tutorial on general terminal commands:
See the following reference article if you were after a list of the most common commands:
This list provides basic Terminal commands within Ubuntu Linux. It gives examples of how they can be used to help troubleshoot specific issues with your computer.
Use the command uname to show what kernel is being used. The kernel is the first section of the operating system to load into memory. It controls such system areas as disk drive management, memory allocation, system processes, and interrupt handler. In the example below, the kernel being used is 3.11.0-15-generic:
user@avalon:~$ uname -a
Linux avalon 3.11.0-15-generic #23-Ubuntu SMP Mon Dec 9 18:17:04 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
user@avalon:~$
Use the command dmesg to show the contents of the boot log. This is a good way to find errors at startup:
user@avalon:~/linux101$ sudo dmesg > dmesg.log
In the example below, the command cat can be used with dmesg to join the contents of the log file. The additional command grep can be used to show any instance of a particular file name occurring in the log, for example, either Intel or error:
user@avalon:~/linux101$ cat dmesg.log | grep intel
[ 1.732400] intel_idle: MWAIT substates: 0x21120
[ 1.732402] intel_idle: v0.4 model 0x3A
[ 1.732405] intel_idle: lapic_timer_reliable_states 0xffffffff
[ 10.148411] fbcon: inteldrmfb (fb0) is primary device
[ 10.922434] i915 0000:00:02.0: fb0 inteldrmfb frame buffer device
[ 10.926448] snd_hda_intel 0000:00:1b.0: irq 50 for MSI/MSI-X
user@avalon:~/linux101$
user@avalon:~/linux101$ cat dmesg.log | grep error
[ 7.478502] EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro
user@avalon:~/linux101$
The command lspci lists all devices that are found on the Peripheral Component Interconnect (PCI) bus:
user@avalon:~/linux101$ sudo lspci > lspci.log
Using the lspci command with the additional commands of cat and grep helps to isolate specific PCI devices, as with Realtek below:
user@avalon:~/linux101$ cat lspci.log | grep Realtek
07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. TRL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 07)
09:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5209 PCI Express Card Reader (rev 01)
09:00.1 SD Host controller: Realtek Semiconductor Co., Ltd. RTS5209 PCI Express Card Reader (rev 01)
user@avalon~/linux101$
Use the command lsmod to list all the loaded mod files within the kernel:
user@avalon:~/linux101$ sudo lsmod > lsmod.log
user@avalon:~linux101$
In Linux, the driver files are loaded as mods. To see which drivers or mods are loaded in the kernel, you can use the cat and grep command. When used with lsmod to search for specific mod files, you can see two examples with Dell and hda below:
user@avalon:~/linux101$ cat lsmod.log | grep dell
dell_wmi 12761 0
sparse_keymap 13948 1 dell_wmi
dell_laptop 17369 0
dcdbas 14847 1 dell_laptop
wmi 19070 1 dell_wmi
user@avalon:~/linux101$
user@avalon:~/linux101$ cat lsmod.log | grep hda
snd_hda_codec_hdmi 41117 1
snd_hda_codec_realtek 55704 1
snd_hda_intel 48171 3
snd_hda_codec 188738 3 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_intel
snd_hwdep 13602 1 snd_hda_codec
snd_pcm 102033 3 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel
snd_page_alloc 18710 2 snd_pcm,snd_hda_intel
snd 69141 17 snd_hda)codec_realtek,snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_pcm,snd_seq,snd_rawmidi,snd_hda_codec,snd_hda_intel,snd_seq,device,snd_seq_midi
user@avalon:~/linux101$
Use the command lsusb to list all the USB devices that are connected to the USB bus:
user@avalon:~/linux101$ sudo lsusb > lsusb.log
user@avalon:~linux101$
You can use this command with the additional cat and grep commands to isolate specific USB devices, as with Intel below:
user@avalon:~/linux101$ cat lsusb.log | grep Intel
Bus 002 Device 003: ID 8087:07da Intel Corp.
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 DEvice 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hib
user@avalon:~/linux101$
Use the ifconfig command to set and query your computer's network settings:
user@avalon:~/linux101$ ifconfig > ifconfig.log
user@avalon:~/linux101$
You can use this command with the additional cat and grep commands to search for inet, which lists your computer's IP addresses:
user@avalon:~/linux101$ cat ifconfig.log | grep inet
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
inet addr:192.168.1.90 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::caf7:33ff:fedb:b2bc/64 Scope:Link
user@avalon:~/linux101$
The following table lists the more basic commands that are used within Linux for troubleshooting purposes. It gives the function and syntax for each:
| Command | Function | Syntax |
|---|---|---|
sudo |
Used before a command to run as root or an administrator. | sudo apt-get update |
ls |
Same as dir; lists the current directory. | ls-ll |
cp |
Copy the file. | cp /dir/filename /dir/filename |
rm |
Delete the file. | rm /dir/filename /dir/filename |
mv |
Move the file. | mv /dir/filename /dir/filename |
mkdir |
Make a directory. | mkdir /dirname |
df |
Report the disk space usage of the file system. | df -h |
dmesg |
Print or control the kernel ring buffer. | dmesg |
lspci |
List all the PCI devices. | lspci |
lsusb |
List all the USB devices. | lsusb |
lsmod |
Show the status of the modules in the Linux kernel. | lsmod |
cat |
Concatenate files and print on the standard output. | cat /dir/logfile |
grep |
Print lines of the input matching a specified pattern. | grep intel |
apt-get |
Update the installer. | apt-get update, or apt-get upgrade |
sosreport |
A utility that collects configuration and diagnostic information about your computer. The utility must be installed first using the following command line: "sudo apt-get install sosreport." It is recommended you reboot your computer after the install before first running the utility. | sosreport |
cat and grep together |
Use to list all the instances of a specific search item. | cat /dir/logfile | grep intel (the output of this command would print to the default output source any instance of the string "intel") |
For additional help troubleshooting your Dell computer, you can contact us from Dell's Support Website.