Easy Shell is a collection of useful boilerplate linux commands for the daily life of every linux user!
All credit goes to lucasviola on GitHub!
This is a basics guide intended to help newcomers and experienced Linux users alike get more comfortable with Bash.
This is not a tutorial or anything of that nature, jjjjkust a collection of useful commands, materials, tips and tricks gathered from around the internet.
This is probably the most important lesson you will ever learn on Linux: man pages are your best friend! Learn to love them.
To access a man page on any linux program just type:
man <program> For example: $ man ps PS(1) User Commands PS(1) NAME ps - report a snapshot of the current processes. SYNOPSIS ps [options] DESCRIPTION ps displays information about a selection of the active processes. If you want a repetitive update of the selection and the displayed information, use top(1) instead. This version of ps accepts several kinds of options: 1 UNIX options, which may be grouped and must be preceded by a dash. 2 BSD options, which may be grouped and must not be used with a dash. 3 GNU long options, which are preceded by two dashes.
- To view currently running programs / processes:
- To view a brief summary on any program:
- You can find out where a file is located by typing:
whereis <program> or
- To change user:
sudo -u <user>
- To change user to superuser (root):
This is not recommended! As a superuser you have the rights modify any file, allowing you to fuck your system if you don't know what you're doing.
- To see your session history:
|is the pipe character and is used to 'pipe' the output from one command into another as the input.
ps lists running processes. That list can be huge, so if we want to search only for processes running which include the word 'init' (hint
grep filters output):
ps -aux | grep init
>>are called angle brackets and are used to redirect output. For example, you can write the output of one command into a file by doing:
echo "any random sentence" >> any-random-file.txt
ps -aux | grep chrome >> any-random-file.txt
There is an important difference between using one and two angle brackets like this. The double angle brackets (
>>) will concatenate, or append to the target file, while the single angle bracket (
>) will overwrite anything that was previously in the target file.
/represents the root directory.
~is an alias for your user's home directory, which usually is:
.represents the current directory
- To decompress a tarball:
tar -xvf <compressed-file.tar.gz>
Note: Flag -v is for verbosity.
- You can call a previously used command pra typing "!" plus the initials of the said program.
For example, let us say you want to edit .bashrc and then open it to edit again:
vim ~/.bashrc exec bash !vim #This will execute the last command on history with the "vim" initials
uname -awill tell you information about your system
df -hwill tell you about your file system disk space
Show all network interfaces
Configure a wireless network interface
Get more information about wireless interface
iwlist <your_interface_here> scan
Check hardware information include about your network, this shows PCIs drivers which is installed or not
Show who is connected in your network
Verify if you have any open port
PS1 environment variable contains the style for the bash cursor:
Export it to your ~/.bashrc file:
export PS1='\u@\h \$'
This will print the following as a cursor:
Some formatting options can be:
\h - The hostname, up to the first ' . ' \H - The hostname. \n - A newline. \t - The time, in 24-hour HH:MM:SS format. \T - The time, in 12-hour HH:MM:SS format. \@ - The time, in 12-hour am/pm format. \u - The username of the current user. \w - The current working directory, with $HOME abbreviated with a tilde. \W - The basename of $PWD, with $HOME abbreviated with a tilde.
Bit bucket (as known as the black hole, one of the linux's special files):
Standard input stream:
Standard outpout streams:
STDERR and STDOUT
Tailing files (getting the last lines)
Outputing whole file content
STDIN to a file (stop with
CTRL + C)
cat > <file>
Reading from file to another file
cat <file1> > <file2>
Reading all lines of file with line numbers
cat -n <file>
Saving output to file (using nano editor, allowing you to edit before saving)
<command> | nano file_name
Searching through the output
<command> | grep <term>
Displaying output in a file-like style (
less allows searching by pressing
<command> | less
<command> | more
Continue running after command. This will not block further running while the program waits on something (network, user input, etc.)
[!] Ignoring file output completely (note that
2 = STDERR and
1 = STDOUT)
<command> > /dev/null 2 > &1
- To change the owner of a directory (recursively):
sudo chown -R newowneruser:newownergroup
- To view actual files permissions
- Example: `drwxr-xr-x`: - First letter is the file type: d | b | c | p | s | \- :---------:|:----------:|:------------:|:----:|:------:|:-----------: directory | block file | special file | pipe | socket | regular file - Second, third and fourth letters are the **user** permissions - Fifth, sixth and seventh letters are the **group** permissions - Eighth, ninth and tenth letters are the **others** permissions - Permissions r | w | x | \- :---:|:-----:|:-------:|:------: read | write | execute | disable - To change the files permissions: - Using letters: - Which users: u | g | o | a :---:|:-----:|:------:|:--: user | group | others | all - Operators: \+ | \- | = :-------------:|:-----------------:|:----------------------------------: add permission | remove permission | changes permissions to the inserted - Permissions: r | w | x :---:|:-----:|:------: read | write | execute - Example: `$ chmod a+w file` add **write** permission for **all** users - Using numbers - Permissions: read | write | execute :---:|:-----:|:------: 4 | 2 | 1 - Example: `$ chmod 754 file` set permission to file: user | group |others :---------------------:|:--------------:|:------: 7 | 5 | 4 read + write + execute | read + execute | read
To list all processes on your system
To list all processes running as root
ps -U root -u root u
To list all processes owned by you
Searching processes by keyword
ps -aux | grep '<keyword>'
Listing it Tree style
ps -aux --forest
Killing a specific process
sudo kill -9 <PID>
Killing all processes except for kill and init
sudo kill -9 -1
Listing local variables
Listing global variables
Printing variable content
$ foo='This is a variable!'
$ echo $foo
Looking for a local variable
set | grep foo
Exporting it to env
$ export foo
$ env | grep foo
Useful environment variables
- $PS1 your prompt setup
- $PATH your path setup
- $USER your current user
The most important files regarding your environment are:
- $ ~/.profile
- $ ~/.bashrc
Both of them are shell scripts and contain instructions which are executed when you log in.
Permanently exporting variables to your PATH:
echo 'export $PATH="$PATH:/path/to/file/"' >> ~/.bashrc
- Where am I?
- Creating Files
- Changing directories
- Moving things around
mv -v <filename> /another/path/
- Deleting things FOREVER
sudo mv -v <filename> /dev/null/
- Copying stuff
cp -v <filename> <another-filename>
- Deleting files
rm -v <filename>
- Deleting folders
rm -vR /path/to/<folder>
- Updating timestamp:
- Listing files and directories
-atells ls to list all files.
- Files starting with
.are hidden files. (Remember this).
- Printing the content of a file:
- Printing the last 2 lines of a file:
tail -n 2 <filename.txt>
- Printing the first 2 lines of a file:
head -n 2 <filename.txt>