How to exract tar.gz/bz2/tbz files :
If Your File Extension is .tar.gz (or .tgz) use this command
tar xvzf file.tar.gz
x: This tells tar to extract the files.
v: This option will list all of the files one by one in the archive. The “v” stands for “verbose.”
z: The z option is very important and tells the tar command to uncompress the file (gzip).
f: This options tells tar that you are going to give it a file name to work with.
** If Your File Extension is .tar.bz2 (or .tbz)**
The major difference between these two is that the z option has been replaced by the j option.
To change password of current user just type:
It will ask you to enter your current password:
[sudo] password for <user>:
And then you will be asked to enter new password:
Enter new UNIX password:
And finally you will be asked to re-enter your password:
Retype new UNIX password:
Note: By default, the keys you press at a command-line password prompt are not displayed at all. They are, however, still registered.
adduser command adds a user to the system. In order to add a new user type:
sudo adduser <user_name>
sudo adduser tom
After typing the above command, you will be prompted to enter details about the new user, such as new password, user Full name, etc.
Below is the information that user will be asked to fill in order to add a new user:
Enter new UNIX password: Retype new UNIX password: passwd: password updated successfully Changing the user information for tom Enter the new value, or press ENTER for the default Full Name : Test User Room Number : Work Phone : Home Phone : Other : Is the information correct? [Y/n] y
(read as bangbang) is a shortcut to repeat the last command entered in console. It is especially useful to run previous command with some changes
adduser: Only root may add a user or group to the system.
Oh snap, what now? Well you could retype the command with sudo in front or you could try
equivalent to sudo "previous command entered"
This is especially useful if the command you just typed is especially long.
It can also be used to change a part of previous commands
To list files and folders inside current directory, we use
[email protected]:/$ ls bin boot cdrom dev etc home initrd.img lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var vmlinuz
ls prints folder structure in simple view, color coded by type. The Ubuntu default colors for
blue for directories, green for executable files, sky blue for linked files, yellow with a black background for devices, pink for image files, and red for archive files.
ls -la will print folder structure with additional info:
[email protected]:/$ ls -la total 104 drwxr-xr-x 23 root root 4096 јул 25 12:40 . drwxr-xr-x 23 root root 4096 јул 25 12:40 .. drwxr-xr-x 2 root root 4096 јул 25 12:42 bin drwxr-xr-x 4 root root 4096 јул 25 12:42 boot drwxrwxr-x 2 root root 4096 јул 25 12:38 cdrom drwxr-xr-x 16 root root 4300 јул 30 12:18 dev drwxr-xr-x 134 root root 12288 јул 30 12:18 etc drwxr-xr-x 5 root root 4096 јул 25 12:50 home lrwxrwxrwx 1 root root 33 јул 25 12:40 initrd.img -> boot/initrd.img-3.19.0-39-generic drwxr-xr-x 23 root root 4096 јул 25 12:42 lib drwxr-xr-x 2 root root 4096 дец 9 2015 lib64 drwx------ 2 root root 16384 јул 25 12:32 lost+found drwxr-xr-x 3 root root 4096 јул 25 14:56 media drwxr-xr-x 2 root root 4096 апр 11 2014 mnt drwxr-xr-x 3 root root 4096 јул 25 13:37 opt dr-xr-xr-x 227 root root 0 јул 30 12:18 proc drwx------ 2 root root 4096 јул 25 13:06 root drwxr-xr-x 23 root root 780 јул 31 14:30 run drwxr-xr-x 2 root root 12288 јул 25 12:46 sbin drwxr-xr-x 2 root root 4096 дец 8 2015 srv dr-xr-xr-x 13 root root 0 јул 30 12:18 sys drwxrwxrwt 8 root root 4096 јул 31 16:05 tmp drwxr-xr-x 10 root root 4096 дец 8 2015 usr drwxr-xr-x 13 root root 4096 дец 9 2015 var lrwxrwxrwx 1 root root 30 јул 25 12:40 vmlinuz -> boot/vmlinuz-3.19.0-39-generic
Another shortcut for
ls -la is
ll. However, this is not a builtin command. Rather its an
alias common in ubuntu systems, in full its
ls -laF. The alias will give you the same output as
ls -la, but with additional slash (
/) at the end of each folder, to help you with easier folder identification.
ll alias can be viewed in full by typing
alias ll. As illustrated below. If the alias is not set then the command will give an error.
[email protected] ~ ->> 08:05 AM Mon Sep 12$ alias ll alias ll='ls -alF'
You can restart ubuntu from command line. Below is example of restarting ubuntu immediately.
You need to have sudo privilege in order to use this command.
Another commands with same results are
sudo shutdown -r now and
sudo init 6.
Easiest and fastest way is with
apt-get command. This command may be considered as lower-level and "back-end", and support other APT-based tools. There are no fancy loaders, only basic progress info. This is fastest way for installing apps.
sudo apt-get install deluge openssh-server
This command will install two new apps: deluge and openssh-server. You can install as many apps as you want in only one line of commands.
"Fancy" way of the same process is wits
sudo apt install deluge openssh-server
Result is the same, but interaction with users is different from previous command.
apt is designed for end-users (human) and it's output may be changed between versions.
Both commands will handle dependencies automatically.
[email protected]:~$ sudo apt install vlc Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: libtimezonemap1 sbsigntool Use 'apt-get autoremove' to remove them. The following extra packages will be installed: libbasicusageenvironment0 libcddb2 libcrystalhd3 libdvbpsi8 libebml4 libfreerdp1 libgnutls28 libgroupsock1 libhogweed2 libiso9660-8 liblivemedia23 libmatroska6 libproxy-tools libresid-builder0c2a libsidplay2 libssh2-1 libtar0 libupnp6 libusageenvironment1 libva-x11-1 libvcdinfo0 libvlc5 libvlccore7 libxcb-composite0 libxcb-keysyms1 libxcb-randr0 libxcb-xv0 vlc-data vlc-nox vlc-plugin-notify vlc-plugin-pulse Suggested packages: firmware-crystalhd freerdp-x11 gnutls-bin videolan-doc Recommended packages: libdvdcss2 The following NEW packages will be installed: libbasicusageenvironment0 libcddb2 libcrystalhd3 libdvbpsi8 libebml4 libfreerdp1 libgnutls28 libgroupsock1 libhogweed2 libiso9660-8 liblivemedia23 libmatroska6 libproxy-tools libresid-builder0c2a libsidplay2 libssh2-1 libtar0 libupnp6 libusageenvironment1 libva-x11-1 libvcdinfo0 libvlc5 libvlccore7 libxcb-composite0 libxcb-keysyms1 libxcb-randr0 libxcb-xv0 vlc vlc-data vlc-nox vlc-plugin-notify vlc-plugin-pulse 0 upgraded, 32 newly installed, 0 to remove and 308 not upgraded. Need to get 10,5 MB of archives. After this operation, 51,7 MB of additional disk space will be used. Do you want to continue? [Y/n]
dpkg stands for Debian Package. This is basic, low-level package installer for Debian and other Debian derivatives.
dpkg have many options, but we are interested in
-i, which stands for
sudo dpkg -i google-chrome-stable.deb
You can install
.deb packages with
If you get an error while installing
.deb package, in most cases you don't have some dependencies. To get rid of this error and install app correctly, run
sudo apt-get -f install without any other parameter. This will search for dependencies and install them before
.deb. Installation will continue and app will be installed.
Using Ubuntu you have different ways to read a text file, all similar but useful in different context.
This is the simplest way to read a text file; it simply output the file content inside the terminal. Be careful: if the file is huge, it could take some time to complete the printing process! If you need to stop it, you can always press
CTRL+C. Note that if you need to navigate through the document, you need to scroll the terminal output.
An improved version of
cat. If your file is longer than the display of the terminal, you can simply type
and you'll have a downwards scrolling display of text, in which you can move down by pressing
This is the
more command with some enhancements, and is typically a better choice than
cat for reading medium to big documents. It opens file showing them from the beginning, allowing to scroll up/down/right/left using arrows.
Once the document is open, you can type some commands to enable some useful features, such as:
q: close immediately the opened file.
/word: search 'word' inside the document. Pressing
nyou can go to the following occurrence of 'word'.
ENTER: scrolls down of a single line.
r: repaints the file content, if it's changing while reading.
This is the best choice for reading medium to big documents.
This software shows only the last part of the file. It's useful if you need to read just a few lines in the end of a very big document.
The above command will show last 10 lines(default) of the file. To read last 3 lines, we need to write:
tail -3 file_name.txt
There's another use case where this command is extremely useful. Imagine to have a empty document, that is filled while you are watching it; if you want to see new lines in real time while they are written to the file without reopening it, just open the file with the
-f option. It's really useful if you are watching some logs, for example.
tail -f file_name.txt
This is the best choice for reading growing documents.
This command does the opposite task of
tail. For example the following command will show the first 15 lines of the file
head -15 file_name.txt
This is an alternative for
tail -f filename .It follows the file changes as they occur and shows you the output.
Some of us like vi, some others like vim. This is not just for reading files, you can also edit them! Now let's see only some features that regards reading documents. Please note that vim offers syntax highlighting.
Once the file is opened, be careful! Don't start typing, or you will mess everything up! In fact, even if you can see the cursor, you have to press
i to start typing and
ESC after you finished typing. By the way, now I'm going to showing you some useful commands that concern reading (not writing):
:: you need to type colon before inserting each of the following commands!
q!: exit from the file without asking a confirm. It's the same as
qif you didn't edit the text.
/word: search for 'word' inside the document.
230: goes to line '230'.
Tip: a shortcut to insert a colon and then type
wq! for writing edits to file and quit without asking a confirm, you can hold down
SHIFT and press twice
This is the best choice for reading code files.
If you know you need a packet <packet>, but you don't know the exact name <packet-exact-name>, instead of searching with Google try with the following:
sudo apt-get update apt-cache search <packet>
This will return you a list of packets name with a description. Once you have identified the exact packet name <packet-exact-name> install it normally:
sudo apt-get install <packet-exact-name>
If you are running a command that returns hundreds of lines, but your interest is just on the lines that contains the word <word>, you should definitely use grep! For example try running:
Check the output, that could be only a few lines or quite long, if you have a server with multiple network interfaces. To show (for example purpose) only the lines that contain 'HWaddr', try using grep:
ifconfig -a | grep HWaddr
Now the output should be much shorter! Generally speaking, you could use grep in the following way:
<command-with-output> | grep <word>
Use the tar (tape archive) command to compress your files and folders. It is similar to creating .ZIP files in Windows environment.
Syntax: tar -zcvf <output tar file> <source file> Example: tar -zcvf outputfile.tar.gz source file
Here’s what those switches actually mean:
-c: Create an archive.
-z: Compress the archive with gzip.
-v: Display progress in the terminal while creating the archive, also known as “verbose” mode. The v is always optional in these commands, but it’s helpful.
-f: Allows you to specify the filename of the archive.