LINUX CMDS

/Linux-

Linux is an open source operating system.

In Linux, We use the command line interface to run the programs .

In Linux Open Source OS we can run an application without having hardware and software requirements.

AWS cloud - it provides all the services that we need a virtual machine or software to run in a local machine.

EC2(Elastic Computing Cloud) - EC2 is a web service where the computing can be resizable.

Cloud computing can be categorized into three groups-

1. Private Cloud.

2. Public Cloud.

3. Hybrid Cloud.

Servers-

1. mail server.

2. web server.

3. proxy server.

4. ftp(file transfer protocol)

Containerisation-

Docker

podman

skopeo

buildah

kubernetes

LINUX COMMANDS-

# - denotes root

$ - denote normal user

AWS cloud-

(instance launch)

sudo yum -y install httpd

cat > index.html(command)

sudo systemctl enable httpd

sudo systemctl start httpd

=================

-whoami

(root) - #

-hostname

your hostname will be displayed.

-pwd

present working directory

-useradd

to add a normal user root can add users.

-passwd user_name

to add the password

-su - user_name

we will switch from root to user

example-

useradd chitransh

passwd chitransh

1234

[root@server ~]# su - chitransh

[chitransh@server ~]$ exit

exit command is used to logout

-ls

this command is used to show all the files inside the root

-cat > chitransh

Hi! there mate

-cat chitransh

Hi! there mate(content will be shown)

-rm chitransh

file will be deleted.

-cp chitransh /sub

bin- cmds that all can access.

sbin- cmds only run by root.

=========================

ssh is used to remote access any server/Telnet

but telnet is not secured enough.

ssh root@

==========================

ls command --

Listing directory content

[root@servera ~]# - what does mean

>root- the user (whether root or normal user)

>servera- name of the host(computer)

~ - this represents that root is in its home

# - this represents the root user

In linux, everything is a file

> hardware

> components

>everything

/ - slash directory(super root)

which includes everything

[root@servera ~]# pwd

pwd- present working directory

> /root

[root@servera ~]# useradd chitransh

[root@servera ~]# passwd chitransh

1234

[root@servera ~]# su - chitransh

[chitransh@servera ~]$ su - root

[root@servera ~]# cd /var

[root@servera var]# pwd

/var

here, instead ~ we have var dir specified after the machine name

which says that this is the home where the root user is.

[root@servera var]# cd

[root@servera ~]# touch file1

touch cmd is used to create an empty file

[root@servera ~]# ls

gives the contents insides the directory(/root)

but it doesnot include the hidden files.

Hidden files- starts with a period(.)

Blue color- Directory

White color- File

[root@servera ~]# ls -a

hidden files also be shown

[root@servera ~]# ls -l

longlisting of directory

[root@servera ~]# ls ll

do the same (long listing)

[root@servera ~]# ls --all

it also show all directory with hidden files(Alter:- ls -l)

[root@servera ~]# ls -r

Reverse order

==============================26/08/21

everything is a file

we need a dir to store a file

we have two user

root- /root

normal- /home

/bin - all cmds

/sbin- system binaries (super user authorisation)

/boot-

redhat linux kernel

(core of os)

> kernel related files

/dev

device files

(hardisk, processor, memory)

/etc

server configuration files

> ip address

> mail server file

/usr

>bin(copy)

>sbin(copy)

>tmp

>local

>unix system resource

>documentation

>help pages

/var

variable types of data

dynamic data

(log files)

/run

removabale devices

pan drive

/tmp

temporary mount point

du -hs cmd - file size

ctrl+c = kill the process

how to creatte a file-

cat > file100

this is my file(ctrl+d)

cat file_name

. current dir

cp file_from_copy file_to

mv - to rename

mv file100 file1009

create a dir-

mkdir dir100

mkdir -p dir100/dir200/dir300-> making a tree

-p is used to create parent dir as well

like-

[root@chitransh ~]# mkdir Videos/blow

error will be shown because Videos folder didnot spell correctly.

[root@chitransh ~]# mkdir -p Videos/blow

if you use this instead blow dir will be created inside the new Videos folder

tree dir100

cd - = previous working dir

cd.. = parent folder

cd ../.. = second parent

rm -rf dir100 - used to delete the filled dir(Without any confirmation)

rm -r dir100 - (ask for confirmation)

rmdir - empty dir

ln dir100/dir200/dir300 rum

>link the path to a file

Questions-

cut/paste- how

when root login - it can be without pass

visual editor-

using vi and vim editor we can create , view and edit the file

how to create a file using vi editor-

>vi file54

(window opens-file editor)

>modes-

1. command mode- vi cmds (create)

2. insert mode(edit - write)

3. execute mode(external command)

4. replace mode(char replace)

5. visual mode(visually seen)

i- switch to insert

Esc key- comout from insert(by default mode is cmd mode)

o-next line with insert mode

O-above the line of cursor

:w - file save

:q - out from vi

:w!- forcefully save

:q!- forcefully exit

:wq - save and exit

:wq! - forcefullly out

:x- save and exit

:x!- force fully

:set nu- line number set

:set nonu

:10- goto line 10

ctrl + shift + ++

vimtutor

how to edit the file-

del the char-

x- one char

3x- three char

dw- to delete one word

3dw-- to delete 3 word

dd- del the line

3dd- del 4 lines

u- undo

how to copy-

yl- copy one char

3yl- 3 char

yw- copy one word

3yw- 3 words

yy- line

6yy- 6lines

p- paste

gg- top

G- bottom

vim-

visual improved

/search word

==================================

User administration and file permission-

User - User is something which performs a certain task.

User-

1. system user- system users are default users created during the linux installation time(root user)

2. normal user- user created by root user for system administration purpose.

3. sudo user- when the normal user is equivalent to root but not root(privilege user)

system user - user id range (0-999)[root user- 0(id)]

normal user - user id (1000-60000)

how to create user-

with useradd command

whenever u create a user with useradd cmd userdatabase file will be updated.

user database file-

/etc/passwd- this file contains user and user related info, havind 7 fields separated by colon.

/etc/shadow- this file contains users passwords and password aging information,having 9 fields separated by colon.

/etc/group- this file contains user's group info having 4 fields separated by colon.

/etc/gshadow- group password info

note:- whenever u create a user , your linux os will create a group and that user belongs to that grp.

bottom 5 lines-

tail -5 /etc/passwd

swapnil:x:1001:1001::/home/swapnil:/bin/bash

1. username

2. user pwd kept in /etc/shadow file in encripted this x link to /etc/passwd to /etc/shadow

3. user id

4. user Primary group id

5. comment field

6. user home directory

7. login shell.

shadow-

swapnil:!!:18871:0:99999:7:::

!!- no password(password stores in second field)

$6$___$ - password encrpted mechanism(rsl algo)

password and hash value combined

creating own id and grp-

> useradd -u 2002 web2

comment field-

> useradd -c developer web3

directory don't want to be the home -

>create a dir

> mkdir dir1

>useradd -d /dir1/user1 user1

changing the shell-

>useradd -s /bin/bourneshell user2

Q. /etc/shadow

fields meanings

user creation and modification -

useranme- ritesh

primary- japan

sec - london

comment- /newhome

loginshell- /bin/sh

useradd -u 2001 -g japan -G london -c student -d /myhome/ritesh -s /bin/sh ritesh

usermod - user updation

userdel- user deleted

delete user's home dir-

userdel -ritesh

-m - move used with directory

Default settings-

cat /etc/default/useradd

su root- switching user without home dir

su - root - switching user with home dir

chsh nisha5-

changing shell

chfn nisha5-

finger information will be stored

{comment}

shadow fields-

1.username

2.!! -password not set

3. last change.

(total no. days )

4. minimum days for change passwd

(validity)

5. maximumdays

6. 7 days earlier messaage before account expiring

7. account enable or disable

8. password expiry date

9. flag(how many chance - to block)

/var/spool/mail- user created (mail box created)

ls /etc/login.defs

chage -l user_name

(password aging information)

chage user_name - to change the password aging

usermod -U nikita- unlocking nikita

user -L nikita- locking

(! in shadow file/encrpted password)

as we create a user mail is created inside /var/spool/mail

so if we delete the user and it is not there in /etc/passwd so why it is not deleted from /var/spool/mail

vim /etc/login.defs

==========================

USERS file and directory permissions-

file is created-

permissions-

owner | group owner | other user

rw- | r-- | r--

420 | 400 | 400

===========

6 4 4

r : read permission(4)

w : write ..(2)

x : execute permission(any programming language file execution)(1)

- : no permission(0)

when a file is creted the permission is by default 6 4 4

owner- all permission

all users - no permission

4 2 1 | - - - | ---

==============

7 0 0

chmod 700 file_name

chmod cmd is used to change the permissions.

chown user_name file_name

chgrp group_name file_name

write-

cat >> file_name

execute-

bash file_name

./file_name or /path/file_name

NOTE-

================================================================

USER 1 USER2

>file1

>file2

we created file1 and file2 inside USER1 and want to access from USER2

>what we gonna do??

owner grp owner others

- rw- | r-- | r-- 1 root root 40 date file_name

we will make user2 as Group owner of file1 then we can access file1 from user2

How to make user2 group admin of user1 -

usermod -g user2 user1(user_name)

if-

the user dir of user1 has all the permission (rwx) to enter

and then the file inside the dir will be given the permission you want to access from user2

================================================================

User file and dir permission-

default permissions for file 644

all permission for file 666

why is default permission is so?

umask is responsible for that.

umask is a numerical value which is used to decide the default permission.

Default permission = Full permission - umask

0666

- 0644

========

0022 -> this is the umask

0777

- 0755

===========

0022

vim /etc/bashrc

vim /etc/profile

umask 0044

changed

-umask value for root user 022

-full permission full-umask= default

-umask 0055- temporary set

/etc/profile or /etc/bashrc

-for user, umask is defined 077 in /etc/login.defs

File backup compression, decompression, searching

-searching using locate and find

create 10 files

example- file1, file2....file10

tar- backup

tar -cvf all.tar *

tar -tvf all.tar

cvf- create verbose(output) file

tvf- used for show the tar file

compress-

gzip all.tar

=========

becomes

all.tar.gz

uncompress-

gunzip all.tar

bzip2 all.tar(more compressed)

bunzip2 all.tar (uncompressed)

==========

xz all.tar(more compressed)

unxz all.tar(uncompressed)

tar -rvf all.tar india123- add new

tar -xvf all.tar india123- extract

delete from archive-

tar --delete -f new.tar file_name

Backup + Compression-

tar -cvzf my.tar.gz file* : gzip

tar -cvjf my.tar.bz2 file* : bzip2

tar -cvJf my.tar.xz file* : xz

searching a file-

locate file_name

locate command not able to search

find cmd-

find / -name file_name

find / -uid ---

find / -gid ---

find / -user user_name

find / -group group_name

find / -size +5M : above 5 mb

find / -size -10G : below 10G

find / -perm 000

---------------------------

updatedb - to update the database of os

locate file_name(redhat)- now it will locate

no permission files-

shadow

gshadow

shadow-

gshadow-

want oto search the string -

grep - content filter

grep word file_name

grep -i word file_name : ignoire case

grep -n word file_name :

starts from root-

grep -n ^root

ends with root-

grep -n root$

only root-

grep ^root$

package management using rpm and yum-

{Redhat linux services and management}

all commmands and configuration files are gonna work only if the package available

rpm - redhat package manager , wecan do pac=kage management using rpm

to search the package-

rpm -qf /etc/passwd

we have two utilities RPM and YUM-

yum remove tree

yum install tree

htttpd(web server package)

- web server commands

- web server configuration file

apache user will be created automatically

To manage the web server we need to start / stop/ restart/ reload the services

-----------------------------

yum remove httpd:- used to remove the package.

yum install httpd:- used to install the package.

yum list httpd:- used to show the package is installed or not.

cat > index.html

cp index.html /var/www/html

is a default location to start the website.

active vs enable

be active but not persistant be active even after rebooting.

all the services-

systemctl list-unit-files :- we can show all the services and their status.

specific services-

systemctl list-unit-files | grep sshd

(services related to sshd will be shown)

services related commands-

systemctl status httpd - used to check the status of service.

systemctl start httpd - to start the service(active)

systemctl stop httpd - to stop(inactive)

systemctl restart httpd- service go down for secs and then up

systemctl reload httpd- solution for service to go down.

systemctl is-active httpd - check the service is active or not.

systemctl enable httpd - service will be stayed after the system iks power off.

systemctl is-enable httpd - check wheather the service is enabled or not.

systemctl disable httpd - to disable the service.

systemctl list-machines

scp package_name root@mynameischitransh:/root

to install-

rpm -ivh package

rpm -q - to query

rpm -e ftp - to erase

rpm -qc package- config files

rpm -qi package - information

rpm -ql package - query list

rpm has dependency problem

yum repolist package

yum info package

Disk Management:-

IDE Controller-

connects with 4 hard disks

- primary master

- primary slave

- secondary master

- secondary slave

/dev/hda

/dev/hdb

/dev/hdc

/dev/hdd

virtual disks:-

/dev/vda

/dev/vdb

/dev/vdc

/dev/vdd

lets take one /dev/sda

MBR - master boot records

disk info

kind of partition:-

primary - max 4 primary

extended- max 1

inside extended partition create logical partition

sda1

sda2

sda3

sda4

we have file system

ext2,ext3,ext4,xfs,gfs

lsblk- lost block device file

/dev/fstab- mount file with disk.

blkid /dev/sdb7

lvm-

-logical volume manager

-disc combination technology

Multiple clubbing disks to create a big space

to create the pv(physical volume)

pvcreate /dev/sdb1 ..more

pvs to verify

vgcreate vg1 /dev/sdb1 /dev/sdb2 /dev/sdb3

vgdisplay

vgextend vg1 /dev/sdb5 - add new

lvcreate -L 500M -n /dev/vg1/lbm1

mkfs -t ext4 /dev/vg1/lvm1

mkdir /a

mount /dev/vg1/lvm1 /a

lsextend

/Linux-

Linux is an open source operating system.

In Linux, We use the command line interface to run the programs .

In Linux Open Source OS we can run an application without having hardware and software requirements.

AWS cloud - it provides all the services that we need a virtual machine or software to run in a local machine.

EC2(Elastic Computing Cloud) - EC2 is a web service where the computing can be resizable.

Cloud computing can be categorized into three groups-

1. Private Cloud.

2. Public Cloud.

3. Hybrid Cloud.

Servers-

1. mail server.

2. web server.

3. proxy server.

4. ftp(file transfer protocol)

Containerisation-

Docker

podman

skopeo

buildah

kubernetes

LINUX COMMANDS-

# - denotes root

$ - denote normal user

AWS cloud-

(instance launch)

sudo yum -y install httpd

cat > index.html(command)

sudo systemctl enable httpd

sudo systemctl start httpd

=================

-whoami

(root) - #

-hostname

your hostname will be displayed.

-pwd

present working directory

-useradd

to add a normal user root can add users.

-passwd user_name

to add the password

-su - user_name

we will switch from root to user

example-

useradd chitransh

passwd chitransh

1234

[root@server ~]# su - chitransh

[chitransh@server ~]$ exit

exit command is used to logout

-ls

this command is used to show all the files inside the root

-cat > chitransh

Hi! there mate

-cat chitransh

Hi! there mate(content will be shown)

-rm chitransh

file will be deleted.

-cp chitransh /sub

bin- cmds that all can access.

sbin- cmds only run by root.

=========================

ssh is used to remote access any server/Telnet

but telnet is not secured enough.

ssh root@

==========================

ls command --

Listing directory content

[root@servera ~]# - what does mean

>root- the user (whether root or normal user)

>servera- name of the host(computer)

~ - this represents that root is in its home

# - this represents the root user

In linux, everything is a file

> hardware

> components

>everything

/ - slash directory(super root)

which includes everything

[root@servera ~]# pwd

pwd- present working directory

> /root

[root@servera ~]# useradd chitransh

[root@servera ~]# passwd chitransh

1234

[root@servera ~]# su - chitransh

[chitransh@servera ~]$ su - root

[root@servera ~]# cd /var

[root@servera var]# pwd

/var

here, instead ~ we have var dir specified after the machine name

which says that this is the home where the root user is.

[root@servera var]# cd

[root@servera ~]# touch file1

touch cmd is used to create an empty file

[root@servera ~]# ls

gives the contents insides the directory(/root)

but it doesnot include the hidden files.

Hidden files- starts with a period(.)

Blue color- Directory

White color- File

[root@servera ~]# ls -a

hidden files also be shown

[root@servera ~]# ls -l

longlisting of directory

[root@servera ~]# ls ll

do the same (long listing)

[root@servera ~]# ls --all

it also show all directory with hidden files(Alter:- ls -l)

[root@servera ~]# ls -r

Reverse order

==============================26/08/21

everything is a file

we need a dir to store a file

we have two user

root- /root

normal- /home

/bin - all cmds

/sbin- system binaries (super user authorisation)

/boot-

redhat linux kernel

(core of os)

> kernel related files

/dev

device files

(hardisk, processor, memory)

/etc

server configuration files

> ip address

> mail server file

/usr

>bin(copy)

>sbin(copy)

>tmp

>local

>unix system resource

>documentation

>help pages

/var

variable types of data

dynamic data

(log files)

/run

removabale devices

pan drive

/tmp

temporary mount point

du -hs cmd - file size

ctrl+c = kill the process

how to creatte a file-

cat > file100

this is my file(ctrl+d)

cat file_name

. current dir

cp file_from_copy file_to

mv - to rename

mv file100 file1009

create a dir-

mkdir dir100

mkdir -p dir100/dir200/dir300-> making a tree

-p is used to create parent dir as well

like-

[root@chitransh ~]# mkdir Videos/blow

error will be shown because Videos folder didnot spell correctly.

[root@chitransh ~]# mkdir -p Videos/blow

if you use this instead blow dir will be created inside the new Videos folder

tree dir100

cd - = previous working dir

cd.. = parent folder

cd ../.. = second parent

rm -rf dir100 - used to delete the filled dir(Without any confirmation)

rm -r dir100 - (ask for confirmation)

rmdir - empty dir

ln dir100/dir200/dir300 rum

>link the path to a file

Questions-

cut/paste- how

when root login - it can be without pass

visual editor-

using vi and vim editor we can create , view and edit the file

how to create a file using vi editor-

>vi file54

(window opens-file editor)

>modes-

1. command mode- vi cmds (create)

2. insert mode(edit - write)

3. execute mode(external command)

4. replace mode(char replace)

5. visual mode(visually seen)

i- switch to insert

Esc key- comout from insert(by default mode is cmd mode)

o-next line with insert mode

O-above the line of cursor

:w - file save

:q - out from vi

:w!- forcefully save

:q!- forcefully exit

:wq - save and exit

:wq! - forcefullly out

:x- save and exit

:x!- force fully

:set nu- line number set

:set nonu

:10- goto line 10

ctrl + shift + ++

vimtutor

how to edit the file-

del the char-

x- one char

3x- three char

dw- to delete one word

3dw-- to delete 3 word

dd- del the line

3dd- del 4 lines

u- undo

how to copy-

yl- copy one char

3yl- 3 char

yw- copy one word

3yw- 3 words

yy- line

6yy- 6lines

p- paste

gg- top

G- bottom

vim-

visual improved

/search word

==================================

User administration and file permission-

User - User is something which performs a certain task.

User-

1. system user- system users are default users created during the linux installation time(root user)

2. normal user- user created by root user for system administration purpose.

3. sudo user- when the normal user is equivalent to root but not root(privilege user)

system user - user id range (0-999)[root user- 0(id)]

normal user - user id (1000-60000)

how to create user-

with useradd command

whenever u create a user with useradd cmd userdatabase file will be updated.

user database file-

/etc/passwd- this file contains user and user related info, havind 7 fields separated by colon.

/etc/shadow- this file contains users passwords and password aging information,having 9 fields separated by colon.

/etc/group- this file contains user's group info having 4 fields separated by colon.

/etc/gshadow- group password info

note:- whenever u create a user , your linux os will create a group and that user belongs to that grp.

bottom 5 lines-

tail -5 /etc/passwd

swapnil:x:1001:1001::/home/swapnil:/bin/bash

1. username

2. user pwd kept in /etc/shadow file in encripted this x link to /etc/passwd to /etc/shadow

3. user id

4. user Primary group id

5. comment field

6. user home directory

7. login shell.

shadow-

swapnil:!!:18871:0:99999:7:::

!!- no password(password stores in second field)

$6$___$ - password encrpted mechanism(rsl algo)

password and hash value combined

creating own id and grp-

> useradd -u 2002 web2

comment field-

> useradd -c developer web3

directory don't want to be the home -

>create a dir

> mkdir dir1

>useradd -d /dir1/user1 user1

changing the shell-

>useradd -s /bin/bourneshell user2

Q. /etc/shadow

fields meanings

user creation and modification -

useranme- ritesh

primary- japan

sec - london

comment- /newhome

loginshell- /bin/sh

useradd -u 2001 -g japan -G london -c student -d /myhome/ritesh -s /bin/sh ritesh

usermod - user updation

userdel- user deleted

delete user's home dir-

userdel -ritesh

-m - move used with directory

Default settings-

cat /etc/default/useradd

su root- switching user without home dir

su - root - switching user with home dir

chsh nisha5-

changing shell

chfn nisha5-

finger information will be stored

{comment}

shadow fields-

1.username

2.!! -password not set

3. last change.

(total no. days )

4. minimum days for change passwd

(validity)

5. maximumdays

6. 7 days earlier messaage before account expiring

7. account enable or disable

8. password expiry date

9. flag(how many chance - to block)

/var/spool/mail- user created (mail box created)

ls /etc/login.defs

chage -l user_name

(password aging information)

chage user_name - to change the password aging

usermod -U nikita- unlocking nikita

user -L nikita- locking

(! in shadow file/encrpted password)

as we create a user mail is created inside /var/spool/mail

so if we delete the user and it is not there in /etc/passwd so why it is not deleted from /var/spool/mail

vim /etc/login.defs

==========================

USERS file and directory permissions-

file is created-

permissions-

owner | group owner | other user

rw- | r-- | r--

420 | 400 | 400

===========

6 4 4

r : read permission(4)

w : write ..(2)

x : execute permission(any programming language file execution)(1)

- : no permission(0)

when a file is creted the permission is by default 6 4 4

owner- all permission

all users - no permission

4 2 1 | - - - | ---

==============

7 0 0

chmod 700 file_name

chmod cmd is used to change the permissions.

chown user_name file_name

chgrp group_name file_name

write-

cat >> file_name

execute-

bash file_name

./file_name or /path/file_name

NOTE-

================================================================

USER 1 USER2

>file1

>file2

we created file1 and file2 inside USER1 and want to access from USER2

>what we gonna do??

owner grp owner others

- rw- | r-- | r-- 1 root root 40 date file_name

we will make user2 as Group owner of file1 then we can access file1 from user2

How to make user2 group admin of user1 -

usermod -g user2 user1(user_name)

if-

the user dir of user1 has all the permission (rwx) to enter

and then the file inside the dir will be given the permission you want to access from user2

================================================================

User file and dir permission-

default permissions for file 644

all permission for file 666

why is default permission is so?

umask is responsible for that.

umask is a numerical value which is used to decide the default permission.

Default permission = Full permission - umask

0666

- 0644

========

0022 -> this is the umask

0777

- 0755

===========

0022

vim /etc/bashrc

vim /etc/profile

umask 0044

changed

-umask value for root user 022

-full permission full-umask= default

-umask 0055- temporary set

/etc/profile or /etc/bashrc

-for user, umask is defined 077 in /etc/login.defs

File backup compression, decompression, searching

-searching using locate and find

create 10 files

example- file1, file2....file10

tar- backup

tar -cvf all.tar *

tar -tvf all.tar

cvf- create verbose(output) file

tvf- used for show the tar file

compress-

gzip all.tar

=========

becomes

all.tar.gz

uncompress-

gunzip all.tar

bzip2 all.tar(more compressed)

bunzip2 all.tar (uncompressed)

==========

xz all.tar(more compressed)

unxz all.tar(uncompressed)

tar -rvf all.tar india123- add new

tar -xvf all.tar india123- extract

delete from archive-

tar --delete -f new.tar file_name

Backup + Compression-

tar -cvzf my.tar.gz file* : gzip

tar -cvjf my.tar.bz2 file* : bzip2

tar -cvJf my.tar.xz file* : xz

searching a file-

locate file_name

locate command not able to search

find cmd-

find / -name file_name

find / -uid ---

find / -gid ---

find / -user user_name

find / -group group_name

find / -size +5M : above 5 mb

find / -size -10G : below 10G

find / -perm 000

---------------------------

updatedb - to update the database of os

locate file_name(redhat)- now it will locate

no permission files-

shadow

gshadow

shadow-

gshadow-

want oto search the string -

grep - content filter

grep word file_name

grep -i word file_name : ignoire case

grep -n word file_name :

starts from root-

grep -n ^root

ends with root-

grep -n root$

only root-

grep ^root$

package management using rpm and yum-

{Redhat linux services and management}

all commmands and configuration files are gonna work only if the package available

rpm - redhat package manager , wecan do pac=kage management using rpm

to search the package-

rpm -qf /etc/passwd

we have two utilities RPM and YUM-

yum remove tree

yum install tree

htttpd(web server package)

- web server commands

- web server configuration file

apache user will be created automatically

To manage the web server we need to start / stop/ restart/ reload the services

-----------------------------

yum remove httpd:- used to remove the package.

yum install httpd:- used to install the package.

yum list httpd:- used to show the package is installed or not.

cat > index.html

cp index.html /var/www/html

is a default location to start the website.

active vs enable

be active but not persistant be active even after rebooting.

all the services-

systemctl list-unit-files :- we can show all the services and their status.

specific services-

systemctl list-unit-files | grep sshd

(services related to sshd will be shown)

services related commands-

systemctl status httpd - used to check the status of service.

systemctl start httpd - to start the service(active)

systemctl stop httpd - to stop(inactive)

systemctl restart httpd- service go down for secs and then up

systemctl reload httpd- solution for service to go down.

systemctl is-active httpd - check the service is active or not.

systemctl enable httpd - service will be stayed after the system iks power off.

systemctl is-enable httpd - check wheather the service is enabled or not.

systemctl disable httpd - to disable the service.

systemctl list-machines

scp package_name root@mynameischitransh:/root

to install-

rpm -ivh package

rpm -q - to query

rpm -e ftp - to erase

rpm -qc package- config files

rpm -qi package - information

rpm -ql package - query list

rpm has dependency problem

yum repolist package

yum info package

Disk Management:-

IDE Controller-

connects with 4 hard disks

- primary master

- primary slave

- secondary master

- secondary slave

/dev/hda

/dev/hdb

/dev/hdc

/dev/hdd

virtual disks:-

/dev/vda

/dev/vdb

/dev/vdc

/dev/vdd

lets take one /dev/sda

MBR - master boot records

disk info

kind of partition:-

primary - max 4 primary

extended- max 1

inside extended partition create logical partition

sda1

sda2

sda3

sda4

we have file system

ext2,ext3,ext4,xfs,gfs

lsblk- lost block device file

/dev/fstab- mount file with disk.

blkid /dev/sdb7

lvm-

-logical volume manager

-disc combination technology

Multiple clubbing disks to create a big space

to create the pv(physical volume)

pvcreate /dev/sdb1 ..more

pvs to verify

vgcreate vg1 /dev/sdb1 /dev/sdb2 /dev/sdb3

vgdisplay

vgextend vg1 /dev/sdb5 - add new

lvcreate -L 500M -n /dev/vg1/lbm1

mkfs -t ext4 /dev/vg1/lvm1

mkdir /a

mount /dev/vg1/lvm1 /a

lsextend

/Linux-

Linux is an open source operating system.

In Linux, We use the command line interface to run the programs .

In Linux Open Source OS we can run an application without having hardware and software requirements.

AWS cloud - it provides all the services that we need a virtual machine or software to run in a local machine.

EC2(Elastic Computing Cloud) - EC2 is a web service where the computing can be resizable.

Cloud computing can be categorized into three groups-

1. Private Cloud.

2. Public Cloud.

3. Hybrid Cloud.

Servers-

1. mail server.

2. web server.

3. proxy server.

4. ftp(file transfer protocol)

Containerisation-

Docker

podman

skopeo

buildah

kubernetes

LINUX COMMANDS-

# - denotes root

$ - denote normal user

AWS cloud-

(instance launch)

sudo yum -y install httpd

cat > index.html(command)

sudo systemctl enable httpd

sudo systemctl start httpd

=================

-whoami

(root) - #

-hostname

your hostname will be displayed.

-pwd

present working directory

-useradd

to add a normal user root can add users.

-passwd user_name

to add the password

-su - user_name

we will switch from root to user

example-

useradd chitransh

passwd chitransh

1234

[root@server ~]# su - chitransh

[chitransh@server ~]$ exit

exit command is used to logout

-ls

this command is used to show all the files inside the root

-cat > chitransh

Hi! there mate

-cat chitransh

Hi! there mate(content will be shown)

-rm chitransh

file will be deleted.

-cp chitransh /sub

bin- cmds that all can access.

sbin- cmds only run by root.

=========================

ssh is used to remote access any server/Telnet

but telnet is not secured enough.

ssh root@

==========================

ls command --

Listing directory content

[root@servera ~]# - what does mean

>root- the user (whether root or normal user)

>servera- name of the host(computer)

~ - this represents that root is in its home

# - this represents the root user

In linux, everything is a file

> hardware

> components

>everything

/ - slash directory(super root)

which includes everything

[root@servera ~]# pwd

pwd- present working directory

> /root

[root@servera ~]# useradd chitransh

[root@servera ~]# passwd chitransh

1234

[root@servera ~]# su - chitransh

[chitransh@servera ~]$ su - root

[root@servera ~]# cd /var

[root@servera var]# pwd

/var

here, instead ~ we have var dir specified after the machine name

which says that this is the home where the root user is.

[root@servera var]# cd

[root@servera ~]# touch file1

touch cmd is used to create an empty file

[root@servera ~]# ls

gives the contents insides the directory(/root)

but it doesnot include the hidden files.

Hidden files- starts with a period(.)

Blue color- Directory

White color- File

[root@servera ~]# ls -a

hidden files also be shown

[root@servera ~]# ls -l

longlisting of directory

[root@servera ~]# ls ll

do the same (long listing)

[root@servera ~]# ls --all

it also show all directory with hidden files(Alter:- ls -l)

[root@servera ~]# ls -r

Reverse order

==============================26/08/21

everything is a file

we need a dir to store a file

we have two user

root- /root

normal- /home

/bin - all cmds

/sbin- system binaries (super user authorisation)

/boot-

redhat linux kernel

(core of os)

> kernel related files

/dev

device files

(hardisk, processor, memory)

/etc

server configuration files

> ip address

> mail server file

/usr

>bin(copy)

>sbin(copy)

>tmp

>local

>unix system resource

>documentation

>help pages

/var

variable types of data

dynamic data

(log files)

/run

removabale devices

pan drive

/tmp

temporary mount point

du -hs cmd - file size

ctrl+c = kill the process

how to creatte a file-

cat > file100

this is my file(ctrl+d)

cat file_name

. current dir

cp file_from_copy file_to

mv - to rename

mv file100 file1009

create a dir-

mkdir dir100

mkdir -p dir100/dir200/dir300-> making a tree

-p is used to create parent dir as well

like-

[root@chitransh ~]# mkdir Videos/blow

error will be shown because Videos folder didnot spell correctly.

[root@chitransh ~]# mkdir -p Videos/blow

if you use this instead blow dir will be created inside the new Videos folder

tree dir100

cd - = previous working dir

cd.. = parent folder

cd ../.. = second parent

rm -rf dir100 - used to delete the filled dir(Without any confirmation)

rm -r dir100 - (ask for confirmation)

rmdir - empty dir

ln dir100/dir200/dir300 rum

>link the path to a file

Questions-

cut/paste- how

when root login - it can be without pass

visual editor-

using vi and vim editor we can create , view and edit the file

how to create a file using vi editor-

>vi file54

(window opens-file editor)

>modes-

1. command mode- vi cmds (create)

2. insert mode(edit - write)

3. execute mode(external command)

4. replace mode(char replace)

5. visual mode(visually seen)

i- switch to insert

Esc key- comout from insert(by default mode is cmd mode)

o-next line with insert mode

O-above the line of cursor

:w - file save

:q - out from vi

:w!- forcefully save

:q!- forcefully exit

:wq - save and exit

:wq! - forcefullly out

:x- save and exit

:x!- force fully

:set nu- line number set

:set nonu

:10- goto line 10

ctrl + shift + ++

vimtutor

how to edit the file-

del the char-

x- one char

3x- three char

dw- to delete one word

3dw-- to delete 3 word

dd- del the line

3dd- del 4 lines

u- undo

how to copy-

yl- copy one char

3yl- 3 char

yw- copy one word

3yw- 3 words

yy- line

6yy- 6lines

p- paste

gg- top

G- bottom

vim-

visual improved

/search word

==================================

User administration and file permission-

User - User is something which performs a certain task.

User-

1. system user- system users are default users created during the linux installation time(root user)

2. normal user- user created by root user for system administration purpose.

3. sudo user- when the normal user is equivalent to root but not root(privilege user)

system user - user id range (0-999)[root user- 0(id)]

normal user - user id (1000-60000)

how to create user-

with useradd command

whenever u create a user with useradd cmd userdatabase file will be updated.

user database file-

/etc/passwd- this file contains user and user related info, havind 7 fields separated by colon.

/etc/shadow- this file contains users passwords and password aging information,having 9 fields separated by colon.

/etc/group- this file contains user's group info having 4 fields separated by colon.

/etc/gshadow- group password info

note:- whenever u create a user , your linux os will create a group and that user belongs to that grp.

bottom 5 lines-

tail -5 /etc/passwd

swapnil:x:1001:1001::/home/swapnil:/bin/bash

1. username

2. user pwd kept in /etc/shadow file in encripted this x link to /etc/passwd to /etc/shadow

3. user id

4. user Primary group id

5. comment field

6. user home directory

7. login shell.

shadow-

swapnil:!!:18871:0:99999:7:::

!!- no password(password stores in second field)

$6$___$ - password encrpted mechanism(rsl algo)

password and hash value combined

creating own id and grp-

> useradd -u 2002 web2

comment field-

> useradd -c developer web3

directory don't want to be the home -

>create a dir

> mkdir dir1

>useradd -d /dir1/user1 user1

changing the shell-

>useradd -s /bin/bourneshell user2

Q. /etc/shadow

fields meanings

user creation and modification -

useranme- ritesh

primary- japan

sec - london

comment- /newhome

loginshell- /bin/sh

useradd -u 2001 -g japan -G london -c student -d /myhome/ritesh -s /bin/sh ritesh

usermod - user updation

userdel- user deleted

delete user's home dir-

userdel -ritesh

-m - move used with directory

Default settings-

cat /etc/default/useradd

su root- switching user without home dir

su - root - switching user with home dir

chsh nisha5-

changing shell

chfn nisha5-

finger information will be stored

{comment}

shadow fields-

1.username

2.!! -password not set

3. last change.

(total no. days )

4. minimum days for change passwd

(validity)

5. maximumdays

6. 7 days earlier messaage before account expiring

7. account enable or disable

8. password expiry date

9. flag(how many chance - to block)

/var/spool/mail- user created (mail box created)

ls /etc/login.defs

chage -l user_name

(password aging information)

chage user_name - to change the password aging

usermod -U nikita- unlocking nikita

user -L nikita- locking

(! in shadow file/encrpted password)

as we create a user mail is created inside /var/spool/mail

so if we delete the user and it is not there in /etc/passwd so why it is not deleted from /var/spool/mail

vim /etc/login.defs

==========================

USERS file and directory permissions-

file is created-

permissions-

owner | group owner | other user

rw- | r-- | r--

420 | 400 | 400

===========

6 4 4

r : read permission(4)

w : write ..(2)

x : execute permission(any programming language file execution)(1)

- : no permission(0)

when a file is creted the permission is by default 6 4 4

owner- all permission

all users - no permission

4 2 1 | - - - | ---

==============

7 0 0

chmod 700 file_name

chmod cmd is used to change the permissions.

chown user_name file_name

chgrp group_name file_name

write-

cat >> file_name

execute-

bash file_name

./file_name or /path/file_name

NOTE-

================================================================

USER 1 USER2

>file1

>file2

we created file1 and file2 inside USER1 and want to access from USER2

>what we gonna do??

owner grp owner others

- rw- | r-- | r-- 1 root root 40 date file_name

we will make user2 as Group owner of file1 then we can access file1 from user2

How to make user2 group admin of user1 -

usermod -g user2 user1(user_name)

if-

the user dir of user1 has all the permission (rwx) to enter

and then the file inside the dir will be given the permission you want to access from user2

================================================================

User file and dir permission-

default permissions for file 644

all permission for file 666

why is default permission is so?

umask is responsible for that.

umask is a numerical value which is used to decide the default permission.

Default permission = Full permission - umask

0666

- 0644

========

0022 -> this is the umask

0777

- 0755

===========

0022

vim /etc/bashrc

vim /etc/profile

umask 0044

changed

-umask value for root user 022

-full permission full-umask= default

-umask 0055- temporary set

/etc/profile or /etc/bashrc

-for user, umask is defined 077 in /etc/login.defs

File backup compression, decompression, searching

-searching using locate and find

create 10 files

example- file1, file2....file10

tar- backup

tar -cvf all.tar *

tar -tvf all.tar

cvf- create verbose(output) file

tvf- used for show the tar file

compress-

gzip all.tar

=========

becomes

all.tar.gz

uncompress-

gunzip all.tar

bzip2 all.tar(more compressed)

bunzip2 all.tar (uncompressed)

==========

xz all.tar(more compressed)

unxz all.tar(uncompressed)

tar -rvf all.tar india123- add new

tar -xvf all.tar india123- extract

delete from archive-

tar --delete -f new.tar file_name

Backup + Compression-

tar -cvzf my.tar.gz file* : gzip

tar -cvjf my.tar.bz2 file* : bzip2

tar -cvJf my.tar.xz file* : xz

searching a file-

locate file_name

locate command not able to search

find cmd-

find / -name file_name

find / -uid ---

find / -gid ---

find / -user user_name

find / -group group_name

find / -size +5M : above 5 mb

find / -size -10G : below 10G

find / -perm 000

---------------------------

updatedb - to update the database of os

locate file_name(redhat)- now it will locate

no permission files-

shadow

gshadow

shadow-

gshadow-

want oto search the string -

grep - content filter

grep word file_name

grep -i word file_name : ignoire case

grep -n word file_name :

starts from root-

grep -n ^root

ends with root-

grep -n root$

only root-

grep ^root$

package management using rpm and yum-

{Redhat linux services and management}

all commmands and configuration files are gonna work only if the package available

rpm - redhat package manager , wecan do pac=kage management using rpm

to search the package-

rpm -qf /etc/passwd

we have two utilities RPM and YUM-

yum remove tree

yum install tree

htttpd(web server package)

- web server commands

- web server configuration file

apache user will be created automatically

To manage the web server we need to start / stop/ restart/ reload the services

-----------------------------

yum remove httpd:- used to remove the package.

yum install httpd:- used to install the package.

yum list httpd:- used to show the package is installed or not.

cat > index.html

cp index.html /var/www/html

is a default location to start the website.

active vs enable

be active but not persistant be active even after rebooting.

all the services-

systemctl list-unit-files :- we can show all the services and their status.

specific services-

systemctl list-unit-files | grep sshd

(services related to sshd will be shown)

services related commands-

systemctl status httpd - used to check the status of service.

systemctl start httpd - to start the service(active)

systemctl stop httpd - to stop(inactive)

systemctl restart httpd- service go down for secs and then up

systemctl reload httpd- solution for service to go down.

systemctl is-active httpd - check the service is active or not.

systemctl enable httpd - service will be stayed after the system iks power off.

systemctl is-enable httpd - check wheather the service is enabled or not.

systemctl disable httpd - to disable the service.

systemctl list-machines

scp package_name root@mynameischitransh:/root

to install-

rpm -ivh package

rpm -q - to query

rpm -e ftp - to erase

rpm -qc package- config files

rpm -qi package - information

rpm -ql package - query list

rpm has dependency problem

yum repolist package

yum info package

Disk Management:-

IDE Controller-

connects with 4 hard disks

- primary master

- primary slave

- secondary master

- secondary slave

/dev/hda

/dev/hdb

/dev/hdc

/dev/hdd

virtual disks:-

/dev/vda

/dev/vdb

/dev/vdc

/dev/vdd

lets take one /dev/sda

MBR - master boot records

disk info

kind of partition:-

primary - max 4 primary

extended- max 1

inside extended partition create logical partition

sda1

sda2

sda3

sda4

we have file system

ext2,ext3,ext4,xfs,gfs

lsblk- lost block device file

/dev/fstab- mount file with disk.

blkid /dev/sdb7

lvm-

-logical volume manager

-disc combination technology

Multiple clubbing disks to create a big space

to create the pv(physical volume)

pvcreate /dev/sdb1 ..more

pvs to verify

vgcreate vg1 /dev/sdb1 /dev/sdb2 /dev/sdb3

vgdisplay

vgextend vg1 /dev/sdb5 - add new

lvcreate -L 500M -n /dev/vg1/lbm1

mkfs -t ext4 /dev/vg1/lvm1

mkdir /a

mount /dev/vg1/lvm1 /a

lsextend

Search This Blog

LINUX

LINUX CMDS

Comments

Post a Comment