ff f

1. ls
normal user ( regular user )
root user
$
#
ubuntu --------------> root
su
sudo su root
_ _ _ _ _ _ _ _ _ _
3 types of permissions
read -- r
write --- w
execute -- x
_ _ _ _ _ _ _ _ _
owner group others
Numerical notation
Alphabetical notation
Numerical notation
-----------------------------
read -- 4
write -- 2
execute -- 1
f2 ---------- rw- rw- r--
f2 --------- rwx rw- r--
r + w +x -- 4 + 2 +1 = 7

2. 7 -- all permissions
chmod 764 f2
chmod 777 f2
read -- 4
write -- 2
execute -- 1
0 - no permissions
1 -- execute
2 -- w
3 -- wx
4 -- r
5 - rx
6 - rw
7 - rwx
chmod 770 f2
chmod 666 f2
chmod 600 f2
chmod 456 f2
chmod 777 d1
++++++++++++++++++++++
Alphabetical notation
owner -- u
group -- g
others -- o
+
-
f2 ---------- r-- r-x rw-
f2 ---------- r-- r-x rwx

3. chmod o+x f2
f2 ---------- r-- r-x rwx
f2 -------- rw- rwx rwx
chmod u+w,g+w f2
chmod u-w,g-w f2
+++++++++++++++++++++++
f50 ------ rw- rw- r--
f50 ------ rw- --x r--
chmod g=x f50
+
-
=
d1
-------- d2
--------------d3
--------------------d4
++++++++++
The Pipe is a command in Linux that lets you use two or more commands,
such that output of one command serves as input to the next.
head -5 f2 | tail -1
date | wc -l
---------------------
An APT repository is a collection of packages
APT repository allows you to perform package install, removal, upgrade operations on individual packages.
tree d1
To install packages
apt-get install packagename

4. Step 1: Update apt repository
Step 2: Install the package
Syntax of Step 1: Update apt repository
sudo apt-get update
Syntax of Step 2: Install the required package
sudo apt-get install package_name
sudo apt-get install tree
To remove the package
sudo apt-get remove tree
-----------------------------------------
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Vi Editor
-------------
Basic editor in linux
To create a file
i - to go to insert mode
:wq -- save and exit
:q! -- exit without saving
Default mode - command mode
Esc - to come out of insert mode to command mode
dd - to delete a line
yy -- to copy the line
p - to paste below
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