If you use Linux, you know that Linux commands can be your strength or your downfall. Linux commands are even more vital if you are a Linux Systems Administrator. Without them, you won’t be able to manage Linux systems. It’s either you know it or you don’t.
With that said, how can we help? How would you like to have a list of very, useful Linux commands at your disposal?
Well, you’re in luck. The Linux commands below are available for you on an easy-to-use page. There is no charge. It is free to use and available anytime you need it. Feel free to come back to this article again and again as a reference for your Linux needs. Enjoy!
The tables below are broken up into different categories for readability. In the table, the column lists the command that should be run on the terminal console of your Linux machine. The second column describes what the command does. The third column describes whether root is required. If root is required, then sudo must accompany the command.
For example, run the command below to show the hardware system components.
sudo dmidecode -qHere are some basic commands that will get you started on learning more about your Linux operating system.
System Information
| Command to run | Description | Requires root? |
|---|---|---|
| uname -r | show used kernel version | No |
| dmidecode -q | show hardware system components (SMBIOS / DMI) | Yes |
| cat /proc/cpuinfo | show CPU information | No |
| cat /proc/interrupts | show interrupts | No |
| cat /proc/meminfo | show memory information | No |
| cat /proc/swaps | show file swap | No |
| cat /proc/version | show version of the kernel | No |
| cat /proc/net/dev | show network adapters statistics | No |
| cat /proc/mounts | show mounted file systems | No |
| lspci -tv | show PCI devices | No |
| lshw | show detailed hardware information | Yes |
| date | show system date | No |
| cal 2008 | show the calendar for 2008 | No |
Important commands to know when you need to reboot or shut down.
Shutdown or Restart a System
| Command to run | Description | Requires root? |
|---|---|---|
| shutdown -h now | power off the system right now | Yes |
| shutdown -r now | restart the system right now | Yes |
| reboot | restart the system right now | Yes |
Learn more about your file system with these commands.
Attaching to a File System
| Command to run | Description | Requires root? |
|---|---|---|
| mkdir /mnt/floppy mount /dev/fd0 /mnt/floppy | attach to a floppy drive | Yes |
| umount /mnt/floppy | unattached the floppy drive | Yes |
| mount /dev/cdrom /mnt/cdrom | attach to a CD or DVD drive | Yes |
| mkdir /mnt/MyFiles mount -t smbfs -o username=myuser,password=mypass //MyComputer/MyFiles /mnt/MyFiles | attach to a Windows network share called MyFiles using the provided Windows credentials | Yes |
Compressing and decompressing files should be part of your arsenal when working with files.
Archives and Compressed Files
| Command to run | Description | Requires root? |
|---|---|---|
| tar cvfz myfile1.tar.gz | create an archive zipped file called myfile1.tar.gz | No |
| tar -tf myfile1.tar | show the contents of an archive file called myfile1.tar | No |
| tar cvf myfile1.tar file1 file2 dir1 | create an archive file containing file1, file2, and directory1 | No |
| gunzip myfile1.gz | uncompress a file | No |
| unzip myfile1.zip | uncompress a file | No |
| tar -xvf myfile1.tar | uncompress the archive file called myfile1.tar | No |
| tar zxvf myfile1.tar.gz | uncompress an archive and zipped file called myfile1.tar.gz | No |
These commands for CDROM come in handy.
CDROM
| Command to run | Description | Requires root? |
|---|---|---|
| mkisofs /dev/cdrom > mycd.iso | create an ISO image from a CD-ROM | No |
| cdrecord -v dev=/dev/cdrom mycd.iso | record data from ISO image mycd.iso to a CD-ROM | No |
| mkdir /mnt/iso mount -o loop -t iso9660 <filename of ISO image> /mnt/iso | View contents of an ISO image from your hard drive | Yes |
Networking with interfaces, rather than people, are also important trades to learn.
Networking
| Command to run | Description | Requires root? |
|---|---|---|
| ifconfig | show configuration of all network interfaces | No |
| route -n | show routing table | No |
| route add -net 192.168.0.0 netmask 255.255.0.0 gw 192.168.1.1 | add a static route to reach network 192.168.0.0/16 via the gateway 192.168.1.1 | No |
| host www.somehost.com | resolve the hostname to IP address | No |
| netstat -tup | show all active network connections and their PID | No |
| netstat -tupl | show all network services listening on the system and their PID | No |
| iwlist scan | show wireless networks | No |
| iwconfig | show configuration of all wireless network interfaces | No |
What packages do you have installed? Learn to install and remove them.
DEB Packages (Debian, Ubuntu)
| Command to run | Description | Requires root? |
|---|---|---|
| dpkg -i package_name.deb | install or upgrade a Debian package | Yes |
| dpkg -r package_name | remove a Debian package from the system | Yes |
| dpkg -l | show all Debian packages installed on the system | No |
| dpkg -s package_name | show information about a specific package installed on the system | No |
| dpkg -L package_name | show list of files provided by a package installed on the system | No |
Files need to be manipulated. These commands will show you how.
Text Manipulation
| Command to run | Description | Requires root? |
|---|---|---|
| cat -n file1 | displays the content of the text file and numbering each row | No |
| tac file1 | displays the content of the text file in reverse order | No |
| tail file1 | displays the last 10 lines of a file | No |
| grep “Feb 9” /var/log/messages | displays each line in the file that contains the words “Feb 9” | No |
| cat file1 | tr a-z A-Z | shows the content of file in upper case letters |
