Linux
6-9-22
- MSDOS – CLI
- MSWIN (GUI)
- UNIX – first cooperate Operating System
o
Powerfull
operating system
o
Command
line interface (CLI)
-
Linux
(CLI & GUI)
o
Open
source OS
o
Unix’s
clone
-
Unix
like family
o
AIX
– IBM
o
HP.UX
– HP
o
Text
User Interface (TUI)
-
.exe
– windows
-
.rpm
– linux – Red hat package management
-
DBN
– Kali linux, Ubuntu
-
Red
hat – Rhel, CentOS, Rocky Linux
-
Types
of OS – 3:
o
Single
User – Single Tasking
§ MSDOS
o
Single
User – Multi Tasking
§ MSWIN
o
Multiuser
– Multi Tasking
§ Unix, linux
-
RHEL
– 7.0, 8.0
o
Bourne Again Shell (BASH)
o
Shell
– SH, KSH, CSH
o
Kernel
– Core Os
§ Mono – linux – uname -a (or) – r
§ Micro – Windows – Systeminfo
o
Kernel
– Device info
§ Multitasking
§ File system info
7-9-22
-
24-8-22
-
DvD,
Pen Drive and
-
ISO.img
(win10)
-
System
(pc)
-
Reboot
-
Bios
→ F1 – F12, del, esc
-
Boot
-
First
boot → Pen Drive
-
F10
– to Save
-
Reboot
-
_
-
A
– Z
-
A,
B → Floppy
-
C
→ HDD
-
_
-
C:\
→ win 10 OS
-
_
-
Linux –
file system Hierarchy
-
/
- top level directory, Parent Directory
-
/root
– Home directory for root user
-
_
-
Admin
→ root - #
-
Guest → normal
- $
-
/home → for
normal user, - 60,000 users can be created in Guest mode
-
/home → is for
normal user, default home directory
-
/boot →
contains bootable files
-
Grub2 → Grant
unified boot loader. – latest version. – RHEL 7.0, 8.0
-
Grub → RHEL
6.0
-
LILO → Linux
loaded, 5.0, 4.0, 3.0, 2.0.
-
/etc →
Configuration files. – Http server configuration files, Shh
-
/bin → binary
Executable Commands
-
/Sbin → Super
user bin
-
/usr → Unix
sharable Resources. – Program files
-
/opt → Option
for USR. – Third Party
25/aug/22
-
/Dev
→ Contain device files
-
/proc →
Process. – Contain virtual information. – Background running tasks (Task
Manager). – file name “ CPU info” – Properties. - $cat/proc/cpuinfo. -
$cat/proc /meminfo -memory information. – Ram, Swap
-
/Run → New
Directory – 7.0 version. – Data, Running services, Login ingo last boot
information. - /run/media – contain removable media (pendrive).
-
/var →
/var/log – login informations
-
/mnt → Empty
directory. – to create a mount point for any partition in Linux
-
/lib → Contain
Library Files
-
/temp → Junk
files
-
/bin →
/usr/bin
-
/sbin →
/usr/sbin
-
/lib →
/usr/lib
-
/lib 64 → /usr
/lib64
-
Srv → service
Terminal –
Linux
-
Right
click – terminal
-
RHEL
6.0, 5.0, 4.0, 3.0, 2.0
o
CTRL
+ alt + T – terminal
-
RHEL
7.0, 8.0
o
Window
key (super key) + terminal (search terminal)
-
Ctrl
+ Shift + ‘+’ → to
zoom text in terminal
-
Ctrl + ‘-‘ →
to zoom out.
-
Prompt –
Commands exequted in Prompt
-
[student@localhost
~]$
o
Username,
machine name, current home direct, normal user
-
~ - tilde
-
[…~]$ su –
root → [root@localhost~]#
-
[username@hostname
~]$ or #
26/8/22
PWD – print
working directory (Absolute path)
-
Present
working directory
o
Ex:
[student@localhost -]$ pwd
o
/home/sudent
-
Su
→ switch user
o
[student….]$
su-root
o
Password:
o
[root@localhost
-]# pwd
o
/root
o
[root@localhost
-]# exit
o
Logout
o
[student@localhost
-]$ su root
o
Password:
o
[root@localhost
student]# pwd
o
/home/student
o
[root@localhost
student]# exit
o
Exit
o
[student@localhost
-]$ su-
o
Password
o
Last
login: ____________
o
[root@localhost]
Char
-
[student@localhost
-]$ char
o
Ctrl
+ l = char
-
Echo
→ Print variable & string value
o
[…]$ echo hi
§ Hi
o
[…]$ echo
hello
§ Hello
o
[…]$ echo $
HOME
§ /home/student
-
Cd → change directory
o
[…]$ cd
desktop
o
[… Desktop]$
echo $Home
§ /home/student
o
[… Desktop]$
pwd
§ /home/student/Desktop
o
[student@localhost
Desktop]$echo$0
§ Bash
o
[…]$echo$BASH
§ /user/bin/bash
o
[…]$echo$SHELL
§ /bin/bash
o
[…]$sh
§ Sh -4.2$echo$0
§ Sh
§ Sh-4.2$exit
·
Exit
§ […]$echo$0
·
Bash
-
Env -
environment
-
[student@localhost
Desktop]$
o
Name=imran
-
[…]$ echo
$NAME
o
Imran
Version
Kernell
-
[…]$
uname -a
-
[…]$
uname -r
Cal – Calendar
print
-
[…]$
cal
-
Opt
– change the behavior
-
$command
opt org
o
Cal
-y 29 03 2023
o
[…]$
cal -y → year calender
o
[…]$ cal
-y 29 03 2023
o
[…]$ cal –help
→ help guide
o
[…]$ cal -1 →
month current
o
$ cal - - one
o
$ cal -3 → 3
months calendar
o
$ cal -s →
Sunday as first day of week
o
$cal -m →
Monday as the first day of week
o
$cal -j →
day’s count in year
o
$ cal -v → cal
command version
o
$ cal -h →
help
o
$ cal -j -m,
$cal -jm
o
$ date → system date
o
$ date + %T →
print’s only time
o
$ date + %B →
month
o
$ date - -help
→ help option
o
$date -s
“yyyy-mm-dd hh:mm:ss”
-
-s → set
-
Shift + Insert
→ select text & command
27/8/22
#timedatectl
-
Only in 7.0 version and more
-
#Timedatectl
set-time “2023-01-01 11:22:44”
o
(time changed)
-
#Timedatectl list-timezones
o
List of time
zones
o
‘Q’- key to
exit
-
#timedatectl
set – timezone “Africa/lagos”
o
Change
time zone
-
#timedatectl
set-timezone “Asia/Kolkata”
-
#timedatectl
set-ntp true
-
$tty
– (Teletypewriter) prints terminal number
-
$su-
-
#timedatectl
- - help
$ id → print the identification of user
-
$ id student
-
$ id root
-
$ id ul
o
No user found
-
$ whoami →
login user name
-
$ su –
-
$ who am i
-
$ who
-
$ w -f → user’s
list
-
$ history
$ cat → concatenation
o
To merge files
-
$ cat >
file1 → to create a file
o
Hello
o
Ctrl + D → to
save file context
-
$
cat >> file1 → to append the file
o
How
o
Ctrl + D → to
save the file
-
$ cat <
file1 → to print the file
o
Hello
o
How
-
$ cat file → to
print to file
-
$ cat >
file2
o
Hi
o
Ctrl + D –
Save
-
$ ls – l
→ list out file names
o
file1
o
file2
-
$ cat file1
file2>file3
o
$ ls – l
o
$
cat file 3 → print file context
-
$ cd Desktop
-
$ PWD
-
$ cat<file1
– print file context
-
$touch –
change file timestamps
-
$touch f1 f2
f3 f4 (f1, f2, f3, f4 are the created file names)
-
$touch k{1…4}
→ to create file k1, k2, k3, k4
-
$touch-d
“yyyy-mm-dd hh:mm:ss” – file name
-
$touch-d
“2022-01-01 11:22:44” file1
29/8/22
MKDIR –
make directory
-
$mkdir
dir1 dir2 dir3 dir4
-
$mkdir
d{1..4}
-
$mkdir
-p li/l2/l3/l4 → (parent & child
directory)
-
ls -R l1
-
$tree l1 →
works only in 8.0 version
-
$mkdir -p
NIT/{linux/{Rhcsa, Rhce}, Windows/{mcsa, mcsc}, oracle/{sql, plsql}}
-
$ ls -R NIT
-
$ tree NIT
$ cp → copy command
-
$ cp file1
file2
-
$ cat file2
-
$ cp file1
new1 → new file creation
-
$ cp file1
dir1
-
$ cd dir1
-
$ ls -l
-
$ ls -l dir1
-
$cp -rvf dir1
dir2
o
Copy directory
to another directory
§ - rvf → move force fully -r vf
o
$ cd (cd..)
(cd../..) (cd ~)
$ pswd
$ mv → (move or cut
paste)
·
It is used to
rename file
·
$ mv file1
file2
·
$ mv file2
new2 → file2 becomes new2
·
$ mv new2 dir2
·
$ mv dir2 dir4
·
$ mv dir3 demo
→ change directory name – rename
$ rm – to delete files
·
Rm file3
·
Rm o* → delete
all ‘o’ named files
§ ‘ * ‘ → Wild card character
§ rm – remove
·
run f*
·
$ rmdir dir1 →
Empty the directory first
·
$ rmdir demo
·
$ rm -rvf dir1
→ delete forcefully ‘r’ is mandatory option
·
$ rm -rvf* →
delete all directories
30/8/22
·
‘-‘ = normal
file
·
‘d’ =
directory
·
‘c’ =
character file (keyboard, mouse)
·
‘b’ = block
file (HDD, pen drive, DvD, CD)
·
‘l’ = link
files
·
$ ls -l
o
‘d'rwx rwxr →
directory
o
‘-‘rw -rw -r--
→ normal file
·
$ div
o
‘c’rw – rw –
rw → character file
·
$ ls – l |grep
^b
·
‘b’rw – rw-- →
block file
$ cd/
·
$ ls – l
·
‘l’rwr rwr →
link file
$ file ‘file name’ →
to know the file type
·
$ file dir1
·
$ file file1
·
$ file
/dev/sda
·
$ file
/etc/password
Symbolic links: Soft
links, Hard links
·
[…]$
cat>soft
o
This is a soft
link
o
$ ls – l
o
$ cd Desktop
o
$ln – s/
home/student/soft
o
$ ls – l
o
$ cat s1
§ This is a soft link
o
$ cat >>
s1
§ This is a linux class
o
$ cat s1
o
$ ls -l
·
du – h → Disk
Usage
o
h – human
readable file
o
$ du – h s1
·
$ inode →
identification number contain properties of the file apart from file
·
$ ls – i s1 →
inode number of s1
·
$ ls – i
/home/student/soft
·
$ rm – rf /home
/student /soft
o
$cat s1
o
$ cat >
soft
o
$ cd Desktop
o
$ cat s1
Hard Link
·
$ cd
·
$ pwd
·
$ cat >
hard
·
$ cat hard
·
$ cd Desktop
·
$ pwd
·
$ ln
/home/student/hard h1
·
$ cat h1
·
$ cat > h1
·
$ cat
/home/student/hard
·
$ du – h h1
·
$ du – h /home
/student /hard
·
$ ls – i h1
·
$ ls – i
/home/student/hard
·
$ rm -rf
/home/student/hard
·
$ cat h1
·
$ ls → list
·
$ ls - l →
long list
·
$ l l → long
list
·
$ ls – al →
all including hidden files
·
$ touch .l1 →
hidden file
·
$ ls – l
·
$ mkdir
.dl → hidden directories
·
$ ls – l f* -
finding files with starting letter ‘f’.
·
$ ls – l i*
·
$ ls – l [FI]*
·
$ ls - l file1 → file details
·
$ ls – ld dir*
→ directories
o
$ ls – ld d*
·
$ touch cat
bat mat fat hat rat tat
o
$ ls – l *at
o
$ ls – l ?at
·
$ ls – l ?? →
two character files
o
$ ls – l ???
o
$ ls – l ????
o
$ ls – l [a –
g]*
·
$ touch abcd
o
ls – l [a-c]*
·
$ ls – l+r
·
$ ls – l
[a-c]* [1-10]*
§ l – long
§ t – time
§ r – reverse
§ R – recursive
2/9/22
·
GUIE –
Graphical User Interface Editor
o
$ gedit
o
$ gvim →
installation needed
·
CLI Editors
o
$vi → visual
display editor (rhel 6)
o
$ vim → visual
display editor improve (rhel 7)
- VIM - Vi IMproved
- version 7.4.160 by Bram Moolenaar et al. Modified by <bugzilla@redhat.com>. Vim is open source and freely distributable.
- <:q> - to exit
- <:help> or <f1> for on-line help
- <:help version7> - for version info
·
Command prompt
o
Rhel 7.0
§ Ctrl + Alt + F2
§ Ctrl + Alt + F2
·
Cli to Gui
o
Rhel 8.0
§ Ctrl + Alt + F3
§ Ctrl + Alt + F2
·
$ vi file1
·
# vi /etc
/passwd
·
# vim /etc
/passwd
·
Vim file
o
i – key
§ command
·
v
·
v
§ : (:wq)
o
Esc
·
# vim file 1
o
Command – i –
insert
§ - - Text - -
§ - Esc – Exit
§ - V – Visual mode
§ :
·
:wq – save file & exit
·
:q – exit
·
:x – save
& quit
·
Shortcuts - Insert
o
A – End of the
line – insert
o
i – insert mode
o
I – starting
of the line
o
a – next
letter
o
o – adding
line below curser
o
O – adding
line above the curser
o
o
Command mode
options
§ gg – starting of page
§ G – end of the page
§ ‘Number’w – word by word curser forward
§ ‘number’b – word by word curser back
§ w – forward direction
§ b – backward direction
§ ndd – to cut the line
§ p – to paste
§ dd –
§ U – undo – u
§ Ctrl + r – redo
§ nyy – copy
§ x – delete
o
Extended
Command mode
§ :wq! – save the context forcefully
§ :x – save & quit
§ / - search the word in the context
§ n – navigate in search result
§ :s/linux/windows – Replace word
§ :s/windows/linux
§ :sc nu – serial number
§ :+ number – number on line
§ :se nonu – remove the line
§ :x – password – vim
·
Vim – o file1
file2
o
Ctrl + w –
navigate b/w files
o
:wqa – save
& quit all
o
$vim tutor
Filter commands: grep,
gels
- Login as a root user
- grep: global regular expression print
- log in as root user to perform grep command
- to find words form context
- to find ‘root’ or any word from file
- cat /etc/password
- file contain huge block content
- # grep /etc/passwd
- # grep root/etc/passwd
- Search word from context
- For with line number
- grep -n student/etc/passwd
- # grep -n (line no) root (search root word) /etc/passwd
- # grep student/etc/passwd
- # grep -n (line no) student (search student word) /etc/passwd
- # grep -v root /etc/passwd (excluding root word)
- # grep -i 'hello' (search word) 'xyz' (file name)
- # grep -nB4 wheel /etc/group
- B - Before, 4 - lines
- # grep -nA4 wheel /etc/group
- #grep -nA6 wheel /etc/group
- #grep --help
- # ls -l | grep ^b
- first letter 'b' files
- ^ - Caret
- # ls -l | grep t$
- last letter from word
- # ls -l | grep sda
- 'sda' word search
- systemctl
- systemctl | grep sshd
- less /etc/passwd
- navigation keys
- 'D', 'P' - previous page, next page
- less command
- V - vim edit
- Q - quit
- pstrhel less
- in file navigate context of file
- ]# less /etc/passwd
- ] # cat etc/passwd
- Using navigation keys in the laptop works, right, left, up, down.
- d – next page
- b – previous page
- few words from file to search from file /bin
- v – vi editor
- i – insert mode
- escape :wq to quit from list
- ]# more /etc/passwd
- Less or more both are same context of file in % more (53%) use enter / to search the word
- ]# head /etc /passwd
- By default starting 10 lines from context
- ]# head -n4 /etc /passwd
- Any numerical value case gt starting 4 lines
- ] # tail /etc/passwd → last 10 lines
- more
- head /etc/passwd
- head -n4 /etc/passwd
- short
- sed
- man sed
- find
- find/-name
- ls -i
- find /- inum 53558113
- find /- type b
- find /- size 10k
- find /-size +10k
- find /- size -10k
- find /- user student
- find /- group student
- ] # grep hello file1
- Hello
- # grep Hello file1
- Hello case sensitive
- cat > file1
- hello
- Hello
- Hello
- hello
- ] # grep – I HELLO file1
- Print → all hello’
- nB6 – before 6lines it will print
- ] # grep – nB4 wheel / etc/ group
- First open the /etc/group
- ] $ cat /etc/group
- #grep – nA4 before 4 lines print
- ] # grep – nA4 wheel/etc/group
- After 4 lines it will print next
- ] # cd/dev
- ls – l
- ] # grep
- ls – l1 grep ^b
- ls – l1 grep t$ - last letter from output
- ls – l1 grep sda – consider as a file name
- sda
- sda1
- sda2
- sda3
- 5/9/22
- man = manual page
- # man man
- #man ls
- #man -k xfs
- xfs: nothing appropriate
- #mandb - installation the software
- #man -k xfs
- #man xfs -growts
- #man passwd
- #man -k passwd
- #man -t password> passwd.ps
- evice = ps document viewer
- #evice passwd.ps
- #lp passwd.ps -p 2-3 pages
- non graphical mode
- File Descriptors or Number channels
- 6/9/22 - 4:00
- MSDOS - CLI
- MSWIN (GUI)
- UNIX - First cooperate operating system
- Powerful Operation system
- Command line Interface (CLI)
- Linux (CLI & GUI)
- Open-source OS
- Unix's Clone
- Unix like family
- AIX - IBM
- HP.UX - HP
- Text user interface (TUI)
- .exe - windows
- .rpm - linux - Red hat package management
- DBN - Kali linux, Ubuntu
- Red Hat - Rhel, Centos, Rocky linux
- Types of OS - 3:
- Single user - single tasking - MSDOS
- Single user - Multi tasking - MSWIN
- Multi user - Multi tasking - Unix/Linux
- RHEL - 7.0, 8.0
- Born Again Shell (BASH)
- Shell - SH, KSH, CSH.
- Kernel - Core OS
- Mono - Linux - uname - a (or) - r
- Micro - windows - systeminfo, msinfo32
- Kernel Device info
- Multitasking
- file system info
- VM care
- create new virtual machine
- typical
- install the O.S later
- Linux
- Red hat Enterprises 7 64 bit
- Virtual
- Virtual Machine name
- client
- Location
- Minimum disk size = 40 GB
- Share Virtual disk as a Single file
- Customize hardware
- Memory - 2 GB
- Processor - 1 core
- 2 core
- New CD / DvD (SATA)
- use image file
- Network Adapter
- Bridge: Connected
- Printers - Remove Printer
- developer.redhat.com
- 7.9
- DvD.Iso
- Localization
- installation source
- software selection
- server with GUI
- System
- Installation Destination
- 40 GB drive
- configure partitioning
- manual partitioning
- new mount point will
- LVM
- +
- /
- 12 GB
- Add mount point
- +
- /boot
- 400 mb
- +
- swap
- 10 GB
- +
- /home
- 8 GB
- Done
- Accept Changes
- Network & Host
- Ethernet
- on
- Hostname
- Done
- Begin Installation
- Root user
- user account (normal user)
- File Decription
- to manage the open files
- file 4 Kernal
- 0 - stdin < - Keyboard
- 1 - stdout >>> - monitor
- 2 - stderr 2> - monitor
- #ls -l > /home/student /Desktop /file1
- save data in file
- #cat /home/student/Desktop/file1
- #ln -l 2> /home/student/Desktop/file2
- 2> = error redirector
- #ls -al
- #ls -al >> /home/student/Desktop/file1
- #file /-name file1
- #file /-name file
- #find /- type b
- #find /-type b2> /dev/null
- error free output
- #find /-type b
- #find /- type b > /home/student/Desktop/f1 2> /home/student/fi2
- #find /-name file2
- #find /-name file2 &> /home/student/Desktop/outfile
- #find/-type b
- #find/-type b &>> /home/student/Desktop/outfile
- &>> - appending the output & error
- User & Group Management System:
- User Management:
- #Useradd
- to create a user
- users
- root
- system
- normal
- #usermod
- to modify a user
- #userdel
- to delete a user
- #passwd
- to assign a password for user.
- username, passwd, uid, gid, comments, home-dir, shell
- root, x, 0, 0, root, /root, /bin/bash
- system user - apache, vsftpd
- apache, x, 1-499 RHEL 6.0, apache, /var/www/html/sbin/nologin
- vsftpd, x, 1-999 RHEL 7.0, 8.0, 1-999 , vsftpd, /var/ftp/pub/sbin/nologin
- Normal User
- student, x, 500 - 60,000 RHEL 6.0, 500 - 60,000 RHEL 6.0, student, /home/student, /bin/bash
- U1, x, 1000 - 60,000 RHEL 7.0, 8.0, 1000 - 60,000 RHEL 7.0, 8.0.
- /etc/passwd
- contain local users properties
- /etc/shadow
- file contain local user passwords
- c/win/sys32/sam/
- file for win passwords
- -l
- modify command user with user mod
- -u
- modify the user id & user mod
- -g
- modify group id
- - c
- to assign the comments
- -d, -m
- modify home directory
- -s
- to change the shall environment
- -L
- to lock the user
- - U
- to unlock the user
- #useradd u1
- #id u1
- #less /etc/passwd
- #tail /etc/passwd
- #useradd u2 -u 2002 -c Hr -d /home/dir2
- -s /sbin/nologin
- - c = assign comments
- - u = assign user id
- - g = print group id
- - d = modify the home directory
- - s = to modify the shell environment
- #usermod -m -d (-md)
- to modify user directory
- #usermod -l "test - user" "u2"
- -----" user nam-nw" "user name old"
- change user name
- # usermod -m -d /home/test-user test-user
- change directory
- # tail /etc/passwd
- use the password to the user
- #passwd u1
- to create a password
- ctrl + c - terminate command
- #usermod -L u1
- lock user
- $su - u1
- pass:_____
- authetication failure
- # passwd -s u1
- #usermod -U u1 (unlock)
- #passwd -s u1
- #tail /etc/passwd
- #userdel test-user
- to delete the user
- #tail /etc/passwd
- #userdel -r u1
- to delete the user & directory
- user passwd management
- #tail etc/shadow
- username, passwd, date, min-age, max-age, passwd-ex-wr, passwd-ex-date, acc-ex-date, black.
- #change: to modify the password properties
- #change -l il
- details of the user password
- #change il
- min: 2, 30, 1, 4, 1
- expiry: 2022 - 10 - 24
- #tail /etc/shadow
- #chage -E 2022 - 10 -22 il
- change expiry date
- #chage - w 2 il
- #chage -l il
- #chage -h (help)
- #chage -d o il
- #chage -l il
- # su -il
- $ chage -l il
- Group Management
- #groupadd
- to create a group
- #groupmod
- to modify a group
- #groupdel
- to delete a group
- #gpasswd
- to assign the passwd to the group
- Group name, Passwd, gid
- redhat , x, 1001
- /etc/gshadow
- passwd properties of group
- /etc/group
- local group properties
- #groupadd redhat
- #tail /etc/group
- #groupadd -g 2002 rhel
- #tail /etc/group
- #groupmod -n linux rhel
- tail /etc/group
- #groupmod -og 2002 redhat
- same uid of group
- #tail /etc/group
- #groupmod -p "1234" linux
- #tail /etc/gshadow
- groupname, password, group admin
- #gpasswd linu
- tail /etc/gshadow
- #gpasswd -r linux
- to remove password
- #tail /etc/gshadow
- groupdel linux
- to delete a group
- #tail /etc/group
- groupdel redhat
- #tail /etc/group
- #useradd u1
- #useradd u2
- #useradd u3
- #useradd u4
- #groupadd redhat
- #usermod -aG redhat u1
- # tail /etc/group
- adding user to group
- #id u1
- #usermod -aG redhat u2
- a = append
- G = secondary group id
- g = primary group id
- # tail /etc/group
- #gpasswd -m u3, u4 redhat
- #tail etc/group
- to add multiple users in group by overwriting the present group users
- #gpasswd - A u1 redhat
- #tail /etc/gshadow
- to make u1 the group admin
- #su - u1
- $ usermod - aG redhat u2 - denied
- $ gpasswd - a u2 redhat
- $ exit
- #tail /etc/gshadow
- #gpasswd - d u3 redhat
- to remove a user
- #vim /etc/login.defs
- to modify the system defaults of users & groups
- password max days - 99
- password min days - 2
- password min length - 5
- password age - 4
- UID_Min 4000
- system accounts
- system UID Max - 201
- system UID Max - 999
- #useradd l1
- #tail /etc/passwd
- #tail /etc/shadow
- #lid -g redhat
- to know group details
- #lid -g redhat | we -l
- to know no.of users
- #wc /etc/passwd
- word, charector counts
- wc -c /etc/passwd
- wc -w /etc/passwd
- $ sudo - su
- snapshot - old OS
- #visudo
- sudo - superuser do
- :97 - to end up in the line 97
- student ALL = (ALL) ALL
- :wq - save & quit
- $sudo su -
- $sudo useradd u1
- $tail /etc/passwd
- #visudo
- :97
- student ALL = (ALL) /sbin/useradd, /sbin/usermod, /sbin/groupadd, /sbin/groupmod, /sbin/fdisk
- limited access to student user
- $ sudo useradd i2
- #which fdisk
- to know the command place (or) located
- #which useradd
- #whichis fdisk
- #visudo
- :97
- Edit: student ALL=(ALL) ALL !/sbin/userdel
- to not give Delete User acces to the user
- $sudo userdel -r l1
- no accepted command
- #visudo
- #storage
- remove "#" hash
- # student All = (All) storage
- student All = (All) storage
- #visudo
- cmnd - Alias COMM = /sbin/useradd, /sbin/usermod, /sbin/fdisk, /sbin/groupadd
- student ALL = (ALL) COMM
- $ sudo useradd i3
- $ sudo useradd i4
- $ sudo userdel
- #visudo
- %wheel ALL=(ALL) ALL
- %redhat ALL =(ALL) NOPASSWD:ALL
- redhat = groupname
- giving group permission
- $ su - i2
- $ sudo userdel -r u1
- $ tail /etc/passwd
- # %wheel ALL (ALL)
- # usermod -aG wheel i4
- # passwd i4
- #useradd rani
- # tail/etc/passwd
- #vim /etc/sudoer.d/rani
- rani ALL=(ALL) NOPASSWD:ALL
- :wq
- sudoer.d = sudoesr directory
- #su - rani
- #fdisk
- #mkdir pepsi
- #ls - ld pepsi - directory details
- drwx r-x r-x 2 root root
- rwx - permittion for user root
- r-x - group owner root
- r-x - other user's permissions
- r - 4 - read
- w - 2 - write
- x - 1 - execute
- # umask 0022
- $umask 0002
- umask = user file creation mask
- - user - group - other
- - 7 - 7 - 7
- 0 - 0 - 2 - 2
- 0 - 7 (rwd) - 5(r-x) - 5(r-x)
- #mkdir dir1
- /s -|d dir1
- #su -
- # umask
- # umask 0020
- # umask
- #mkdir redbull
- #ls - l
- closing terminal will change the umask value
- #su
- #umask
- #touch file1
- #ls - l file1
- #ls - ld pepsi
- file umask value
- U - G - O
- 6 6 6
- 0 0 2 2
- 0 - 6(rw-) 4(r-1) 4(r-)
- #touch file1
- #ls -l file1
- -rw -r - r --1 root root 0 sep 24 16:50 file1
- # ls - ld pepsi
- drwx r-x r-x 2 root root 6 sep 24 16:18 pepsi
- # vim /etc/bashrc (normal user umask user)
- 002 = 000 (1) value
- $ umask
- 0000
- # su -
- # vim /etc/profile
- 020 (2) value
- #source /etc/profile
- #umask
- 0020
- #vim /etc/login.defs
- #useraddd u1
- #cd /home/
- ls - l
- #vim /etc/login.defs
- umask = 070
- to give permissions to create other user permission to "u2" user
- #useradd u2
- #ls -l
- #cd
- #chmod
- to change the existing files umask
- #chmod u+, -, = rwx, g+, -, =rwx, o+, -, =rwx filename
- #chmod u-x, g+w, o=r pepsi
- #ls - l
- # chmod - R u-x
- #chmod -R a+, -, =rwx filename
- #chmod -R u-x, g+w, o=r pepsi
- #chmod a = rwx pepsi
- #ls -ld pepsi
- #chmod -R 755 filename
- df - th
- yum install httpd -y
- Naming standards
- #chown
- to change the ownership
- #chown ' username ' ' directory ' or ' filename '
- #mkdir pepsi
- #ls - ld pepsi
- #chown student pepsi
- #ls - ld pepsi
- #chown -R student pepsi
- to change ownership with recursive (means giving ownership of every directory & files ownership in the directory)
- #chgrp - group name file name
- #chgrp - change group ownership
- #useradd u1
- #useradd u2
- #groupadd redhat
- #usermod -aG redhat u1
- #usermod -aG redhat u2
- #id u1
- #id u2
- #chgrp redhat pepsi
- #ls -ld pepsi
- drw r-x r-x, 2 student redhat 6 sep 26 16:24 pepsi
- #cd pepsi
- #su u1
- $touch abcd
- $exit
- #cd
- #chmod g+w pepsi
- #ls - ld pepsi
- #cd pepsi
- #su u1
- $touch xyz
- $ls -l
- $exit
- #chown student:redhat redbull
- #mkdir redbull
- ls - ld redbull
- special permissions:
- s - special & executive permittion
- S -
- S s x 0022
- User:
- setuid
- suid
- #chmod u+s filename (or) #chmod 4755 filename (only for executable files)
- Group:
- setgid
- sgid
- #chmod g + s dir name (or) #chmod 2775 dir name
- other users (sticky permissions)
- #chmod o + t dirname (or) #chmod 1757 dir name (only for dirs)
- #fdisk - l (normal user cannot access it)
- $ su -
- # which fdisk
- # ls - l /sbin/fdisk
- # chmod u + s /sbin/fdisk
- $ ls - l /usr/bin/passwd
- $ su -
- #mkdir 7up
- #ls -ld 7up
- #useradd il
- #useradd i2
- #groupadd rhel
- #usermod -aG rhel il
- #usermod -aG rhel i2
- #id i1
- #id i2
- #chgrp rhel 7up
- ACL: Access Control List
- user's - root directory
- group - user1, user2
- root - Directory
- #getfacl filename
- to list the acls
- #setfacl -m u (or) user: 'username' :rwx,g (or) group: 'groupname' :rwx, o::r -- filename
- #useradd Jani
- #useradd Das
- #useradd Mahesh
- #useradd Rani
- #useradd Vani
- #groupadd NIT
- #usermod -aG NIT Rani
- #usermod -aG NIT Vani
- #mkdir oppo
- #ls - ld oppo
- drwxr-xr-x. 2 root root 6 sep 27 16:31 oppo
- . (or) +, acl function
- 2 - directory count
- #getfacl oppo
- #setfacl -m u:jani:rwx, g:NIT:rwx, o::r-- oppo
- #ls - ld oppo
- drwx rwx r-- + 2 root root
- #getfacl oppo
- #cd oppo
- #su Jani
- $touch j1
- $ls -l
- #su Rani
- $touch R1
- $ls -l
- $exit
- #su Vani
- $touch v1
- $ls - l1
- $exit
- #getfacl oppo
- -
- -
- -
- mask::rwx
- -
- #setfacl -m m::r -- oppo
- #getfacl oppo
- to restrict user's & groups to access this directory
- m = mask
- #cd oppo
- #su Rani
- $ touch r2
- $ exit
- # cd
- # setfacl -m m::rwx oppo
- # getfacl oppo
- #cd oppo
- #ls -l
- #mkdir dir1
- #ls -l
- Default ACL Permittion:
- #setfacl -R -m m::r -filename
- #setfacl -m d:u:username :rwx oppo
- #cd
- #setfacl -m d:u:Das:rwx oppo
- #getfacl oppo
- #cd oppo
- #su Das
- $touch D1
- denied
- $mkdir dir2
- $ls - l
- $getfacl dir2
- $exit
- #cd
- #cd oppo/dir2
- #su Das
- $touch l1
- $ls -l
- $pwd
- #getfacl oppo
- #mkdir redmi
- #getfacl redmi
- #ls -ld redmi
- #getfacl oppo | setfacl -- set - file = - redmi
- copy rules of one directory to another directory
- #getfacl redmi
- #ls -ld redmi
- #setfacl -x u:Jani oppo
- to remove permissions
- #getfacl oppo
- #setfacl -x g: NIT oppo
- #getfacl oppo
- #setfacl -b oppo
- -b = to remove acl from oppo directory
- #getfacl oppo
- Process mangement:
- a process is a running instance of a launched, executable program
- Rhel 7.0, 8.0 - SystemD - PID - 1
- Rhel 6.0, 5.0, 4.0, 3.0, 2.0 initd - PID - 1
- #ls - l
- #gedit file1
- [1]+ stopped - stop foreground task
- #jobs
- to know status of other working directories
- #fg %1
- foreground task
- ctrl + c - to terinated gidit
- ctrl + z - to stopped gidit
- Sleeping command
- S - process intruptable
- D - process unintruptable
- K - process killable
- #sleep 10000
- ctrl + z
- stopped
- #jobs
- #bg %1
- #jobs
- #ls - l
- #gedit file1 &
- & - to run the process in the background
- #jobs
- #fg %2
- #jobs
- S - Intruptable process
- T - process stop
- C - zomic
- + - present process
- #ps aux | less
- #ps aux | less
- #jobs
- #fg %1
- ctrl + z
- to stop
- jobs
- #fg %2
- #ps ef
- #ps if
- #kill -l (signal)
- #jobs
- [1]+
- #kill -18 %1 (start)
- #jobs
- #kill -19 3909 (stop)
- #kill -15 3909
- #gedit file1 &
- #jobs
- #kill -1 %1
- #jobs
- #systemctl status sshd.service
- $ipaddr
- #systemctl restart network
- #ip addr show eno16777736
- #exit
- $ssh root@192.168.1.17
- #exit
- $su - root
- #exit
- #vim /etc/ssh/sshd - config
- #permit Root login - no
- #exit
- $ssh root@192.168.1.17
- #exit
- $su -
- #systemctl status sshd.service
- #kill -1 1967
- #exit
- $ssh root@192.168.1.17
- $su-
- #jobs
- #sleep 10000 &
- #jobs
- #kill -9 %1
- #jobs
- #sleep 10000 &
- #sleep 20000 &
- #jobs
- #killall -19 sleep
- 19 - stopped
- #jobs
- #killall - 18 sleep
- 18 - running
- #jobs
- #killall -15 sleep
- 15 - terminate
- #Pkill -t pts/1 -19 sleep
- pts/1 - terminal number
- #pkill -t pts/1 -18 sleep
- D - uniterruptable sleep
- R - running or runnable
- S - interruptable sleep
- T - Stopped
- t - stopped tracing
- x - dead
- < - high priority
- How to know the CPU load Average?
- #uptime
- #lscpu or cat proc/cpuinfo
- #grep "model name" /proc/cpuinfo
- #grep "model name" /proc/cpuinfo | wc
- #grep "model name" /proc/cpuinfo /wc - l
- #uptime - to know the system load average
- top - options
- process
- 1 to 19 - low priority
- 0 - Normal priority
- -1 to -20 - high priority
- #nice
- #renice
- #sleep 20000 &
- #jobs
- #ps aux pid, comm
- #gnome - system - monitor
- #su
- #man ps
- uptime
- grep "model name" /proc/cpuinfo
- top
- ps aux
- ps axo pid,comm,nice --sort=nice
- ps ao pid,comm,nice --sort=nice
- sleep 10000 &
- ps ao pid,comm,nice --sort=nice
- nice -n 19 gedit file1 &
- jobs
- ps ao pid,comm,nice --sort=nice
- renice -n -20 4394
- ps ao pid,comm,nice --sort=nice
- ps aux
- ps ao pid,comm,nice --sort=nice
- renice -n 19 4375
- ps aux
- ps ao pid,ppid,sid,gid
- kill -15 3774
- kill -9 3774
- ps ao sid,ppid,pid
- ps ao sid,ppid,pid,comm
- How to manage System demon & init demon
- Rhel 6.0 - initd - PID1
- Rhel 7.0 - systemd - PID1
- #systemctl
- #systemctl -l
- Q - to quit
- #systemctl --type = service
- #systemctl --type = target
- #systemctl status sshd.service
- #systemctl restart sshd.service
- #systemctl status sshd.service
- #systemctl is - active sshd.service
- #systemctl is - enabled sshd. service
- #systemctl disable sshd. service
- #systemctl status sshd
- #systemctl status sshd.service
- #systemctl status firewalld.service
- #systemctl mask firewalld. service
- #systemctl stop firewalld.service
- #systemctl status firewalld.service
- #systemctl unmask firewalld.service
- #systemctl status firewalld.service
- systemctl
- systemctl --type=service
- systemctl --type=service --all
- systemctl --all
- systemctl
- systemctl --type=target
- systemctl --type=service
- systemctl --type=service --all
- systemctl list-unit-files
- systemctl | grep sshd
- systemctl status sshd.service
- systemctl stop sshd.service
- systemctl status sshd.service
- systemctl start sshd.service
- systemctl status sshd.service
- systemctl restart sshd.service
- systemctl status sshd.service
- systemctl reload sshd.service
- systemctl status sshd.service
- systemctl is-active sshd.service
- systemctl is-enabled sshd.service
- systemctl stop sshd.service
- systemctl status sshd.service
- reboot
- systemctl status sshd.service
- systemctl disable sshd.service
- systemctl status sshd.service
- reboot
- systemctl status sshd
- systemctl enable sshd
- reboot
- systemctl status sshd.service
- systemctl status firewalld.service
- systemctl mask firewalld.service
- systemctl status firewalld.service
- systemctl stop firewalld.service
- systemctl status firewalld.service
- systemctl start firewalld.service
- reboot
- systemctl status firewalld.service
- systemctl unmask firewalld.service
- systemctl status firewalld.service
- reboot
- systemctl status firewalld.service
- systemctl list-dependencies sshd.service
- service sshd status
- service sshd start
- service sshd stop
- Packages
- #rpm -qi tree
- to query package info
- #rpm -qd tree
- to query doc to package
- #rpm -ql tree
- to query list the package
- #rpm -qc vsftpd
- to query the config files
- #rpm -Uvh vsftpd
- to update the package
- #rpm -e vsftpd
- to uninstall the package
- #cd /etc/yum.repos.d/
- root@localhost packages
- #ls -l
- #vim rhel.repo
- [rhel]
- name = redhatx64
- baseurl = 'file://run/media/student/RHEL - 7.0 server.x86_64
- gpgcheck = 0
- enable = 1
- :wq
- #yum clean all
- #cd
- #yum install httpd -y
- #yum list vsftpd
- #yum list bind
- #yum list all
- #yum list
- #yum provides
- #yum search all
- #yum search all "dns server"
- #yum group list
- #yum group install "Development
- #yum info httpd
- #yum update httpd* -y
- #yum history
- #yum history undo 4
- cd /run/media/student/RHEL-7.0\ Server.x86_64/
- pwd
- ls
- cd Packages
- cd ..
- cd Packages
- ls -l
- tree
- ls -l tree-1.6.0-10.el7.x86_64.rpm
- rpm -ivh tree-1.6.0-10.el7.x86_64.rpm
- tree
- rpm -q tree
- rpm -q vsftpd
- rpm -qa
- rpm -qa | grep tree
- rpm -qd tree
- rpm -ql tree
- rpm -qi tree
- rpm -qc tree
- rpm -ivh vsftpd-3.0.2-9.el7.x86_64.rpm
- rpm -q vsftpd
- rpm -qc vsftpd
- rpm -Uvh vsftpd-3.0.2-9.el7.x86_64.rpm
- tree
- rpm -e tree
- tree
- rpm -q tree
- rpm -ivh httpd*
- yum repolist all
- yum install httpd*
- cd /etc/yum.repos.d/
- ls -l
- vim rhel.repo
- yum clean all
- yum repolist all
- yum install httpd* -y
- yum list httpd
- yum list tree
- yum list all
- yum search all "web server"
- yum provides /var/www/html
- yum info httpd
- yum install tree.x86_64
- yum install tree.x86_64 -y
- yum grouplist
- yum groupinstall "Development Tools" -y
- yum remove httpd* -y
- yum update tree
- yum history
- yum history undo 5
- yum history
- Disk Partition theory
- Disk Partition
- command 'm' for help
- #fdisk -l
- #fdisk /dev/sda
- command (m for help): p
- command: n
- to create partition
- select: p
- partition number: 3
- first sector:
- last sector: +2G
- 2gb memory
- command: p
- command: n
- partition type:
- select: p
- last sector: +2g
- command: p
- command: n
- command: d
- delete partition
- command: p
- command: n
- select: e
- command: p
- command: n
- command: p
- print partition table
- logical driver & Primary Partition
- command: w
- #partprobe /dev/sda
- #kpratx /dev/sda
- fdisk -l
- part
- #mkfs.xfs
- #mkfs -t xfs /dev/sda3
- #blkid /dev/sda3
- #df
- #cd /mnt
- #touch abcd xyz file1 file2
- #mkdir dir {1...4}
- #ls -l
- #df -Th
- #mkdir /home/student/Desktop/dir1
- #mount /dev/sda3/home/student/desktop/dir1
- #cd
- Permanent Mount Point
- #vim/etc/
- /dev/sda3 /home/student/
- Desktop/dir1 xfs
- defaults 0 0
- :wq
- #mount -a
- #cd /home/student/Desktop
- #ummount /dev/sda3
- #vim/etc/
- partprdx/dev/sda
- Swap Partition:
- #free -m
- #command:p
- #mkswap /dev/sda3
- #blkid /dev/sda3
- #swapon /dev/sda3
- #free -m
- #swapon -s
- #reboot
- to reboot system
- #free -m
- #swapoff /dev/sda3
- #free
- #vim /etc/fstab
- #partprobe /dev/sda
- LVM
- logical volume management
- #lsblk
- to know partition details
- #fdisk /dev/sda
- :n
- :t
- :8e
- :w (save)
- #pvcreate
- Physical Volume Create
- #vgcreate
- Volume Create
- #pvs
- #pvdisplay /dev/sda3
- #vgs
- #vgdisplay
- #lvcreate -L 400m -n my_lv my_vg
- #lvs
- #lvdisplay
- #lvscan
- #mkfs -t ext4 /dev/my-vg
- #blkid /dev/my-vg/my-lv
- #mount/dev/my-vg/my-lv/mnt
- #mount
- #df-Th
- #cd /mnt/
- #touch abcd xyz file1 file2
- #mkdir
- Permanent Mount Point
- #df -Th
- #mkdir /home/student/Desktop/dir1
- #vim/etc/fstab/dev/mg-vg/my-lv/home/student/Desktop/dir1
- #mount -a
- How to increase size of a LVM disk
- #lvextend -L +200M /dev/my-vg/my-lv
- #df-Th
- #resize 2fs /dev/my-vg/my-lv
- #df-Th
- #lvscan
- To Decrease size of Lvm disk
- #unmount /dev/my-vg/my-lv
- #e2fsck -f /dev/my-vg/my-lv/400m
- #lvreduce -L -200m /dev/my-vg/mg-lv
- #mount -a
- #
- #vgextend my-vg /dev/sda5
- #vgs
- #pvs
- Transfer file
- #pvmove /dev/sda3 /dev/sda5
- #pvs
- Remove vg
- #vgreduce my-vg/dev/sda3
- Delete LVM
- #lvremove /dev/my-vg/my-lv
- #unmount /dev/my-vg/my-lv
- #vim /etc/fstab
- #mount -a
- #lv remove /dev/my-vg/
- Create vg called 'red hat' with 16PE and create LV called fedora with 15LE assign exth file system mount on/test dir
- 16 * 15 = 240
- #fdisk /dev/sda
- :n
- :p
- Network
- NIC
- MAC
- Media Access Control
- 'getmac' - command
- 'ipconfig /all' - command
- Ethernet & Internet
- stp or utp cable
- cat6 cable
- fiber cable
- radio frequency
- infrared
- HUB
- it is not an intelligent device
- it will work with bits (0,1)
- use broadcast for communication
- it will share the Bandwidth
- it is having half duplex communication
- Switches
- it is an intelligent device
- it maintains the mac address
- using floating & unicast for communication
- Each port of the switch has fixed bandwidth
- having full duplex communication
- Router
- enable communication between two different devices
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