How to know Linux OS is 64 bit or 32 bit ?

 How to know Linux OS is 64 bit or 32 bit  ?

First Method :

[root@0.0.0.0]#

[root@0.0.0.0]# which arch

/usr/bin/arch

[root@0.0.0.0]#

[root@0.0.0.0]#

[root@0.0.0.0]#

[root@0.0.0.0]# arch

x86_64

[root@0.0.0.0]#

[root@0.0.0.0]#

[root@0.0.0.0]#

Second Method :

[root@0.0.0.0]# uname -a

Linux ip-172-31-19-40.ec2.internal 4.18.0-425.19.2.el8_7.x86_64 #1 SMP Fri Mar 17 01:52:38 EDT 2023 x86_64 x86_64 x86_64 GNU/Linux

[root@0.0.0.0]#

This is 64 bit Operating System because of output is x86_64

How to get metadata details for AWS EC2 instance using curl command

 Get metadata details for AWS EC2 instance using curl command 

[root@]# curl http://169.254.169.254/2018-09-24/meta-data

ami-id

ami-launch-index

ami-manifest-path

block-device-mapping/

events/

hibernation/

hostname

identity-credentials/

instance-action

instance-id

instance-type

local-hostname

local-ipv4

mac

metrics/

network/

placement/

profile

public-hostname

public-ipv4

public-keys/

reservation-id

security-groups

services

Example: 

[root@]# curl http://169.254.169.254/2018-09-24/meta-data/security-groups

kpitdb-demo-db-sg

Adding Users to Sudoers in Linux

 

Adding Users to Sudoers in Linux

Login as root user : visudo and check wheel (group) details should be there 

## Sudoers allows particular users to run various commands as

## the root user, without needing the root password.

##

## Examples are provided at the bottom of the file for collections

## of related commands, which can then be delegated out to particular

## users or groups.

##

## This file must be edited with the 'visudo' command.

## Allows people in group wheel to run all commands

%wheel  ALL=(ALL)       ALL

## Same thing without a password

# %wheel        ALL=(ALL)       NOPASSWD: ALL

Login as root user to add user (atharv) in wheel group (sudoers)

[root@0.0.0.0~]# usermod -aG wheel atharv

[root@0.0.0.0~]#

[root@0.0.0.0~]#

[root@0.0.0.0~]#

[root@0.0.0.0~]#

[root@0.0.0.0~]# id atharv

uid=1002(atharv) gid=1002(dba) groups=1002(dba),10(wheel)

[root@0.0.0.0~]#

Login as atharv user 

[atharv@0.0.0.0 ~]$ su - atharv

Password:

Last login: Thu May 18 11:50:13 UTC 2023 on pts/1

[atharv@0.0.0.0 ~]$

[atharv@0.0.0.0 ~]$

[atharv@0.0.0.0 ~]$ sudo fdisk -l

Disk /dev/xvda: 60 GiB, 64424509440 bytes, 125829120 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disklabel type: gpt

Disk identifier: 2E431796-24CD-41A3-A4CB-7987FFF67072

Device     Start       End   Sectors Size Type

/dev/xvda1  2048      4095      2048   1M BIOS boot

/dev/xvda2  4096 125829086 125824991  60G Linux filesystem

[atharv@0.0.0.0 ~]$

[atharv@0.0.0.0 ~]$

[atharv@0.0.0.0 ~]$ sudo ls -la /root

total 260816

dr-xr-x---.  9 root root      4096 May 18 11:12  .

dr-xr-xr-x. 21 root root      4096 Jan 13 14:03  ..

-rw-------.  1 root root      6953 May  4  2021  anaconda-ks.cfg

drwx------   4 root root        27 Apr 14 10:20  .ansible

drwxr-xr-x   3 root root        22 Apr 14 10:14  ansible

-rw-r--r--   1 root root  77218345 Jan  9 18:30 'AutoDL?BundleId=247937_0ae14417abb444ebb02b9815e2103550'

-rw-r--r--   1 root root    137320 Feb 18 13:07  aws_replication_agent_installer.log

-rw-r--r--   1 root root     25289 Feb  6 10:25  aws-replication-installer-init.py

-rw-------.  1 root root     17257 May 18 11:12  .bash_history

-rw-r--r--.  1 root root        18 Aug 12  2018  .bash_logout

-rw-r--r--.  1 root root       176 Aug 12  2018  .bash_profile

-rw-r--r--.  1 root root       176 Aug 12  2018  .bashrc

drwx------   3 root root        20 Sep 21  2022  .config

drwxr-xr-x   6 root root        95 Sep 21  2022  .cpan

drwxr-xr-x   3 root root        55 Sep 21  2022  .cpanm

-rw-r--r--.  1 root root       100 Aug 12  2018  .cshrc

-rw-r--r--   1 root root 189609546 Dec  7 23:14  jdk-19_linux-x64_bin.rpm

drwxr-xr-x   3 root root       105 Feb 18 13:01  mgn18022023

-rw-------.  1 root root         0 May 16 17:02  original-ks.cfg

-rw-------   1 root root      3167 Nov  8  2022  .psql_history

drwx------.  2 root root        48 Apr 14 10:25  .ssh

-rw-r--r--.  1 root root       129 Aug 12  2018  .tcshrc

-rw-r--r--   1 root root       111 May 18 10:44  test.txt

-rw-------   1 root root      1047 May 18 08:41  .viminfo

-rw-------   1 root root       518 May 18 05:50  .Xauthority

[atharv@0.0.0.0 ~]$

[atharv@0.0.0.0 ~]$

[atharv@0.0.0.0 ~]$

[atharv@0.0.0.0 ~]$

[atharv@0.0.0.0 ~]$

How to Add or Remove Linux User From Group : Linux OS

How to Add or Remove Linux User From Group ?

Add the User to a Group in Linux

[root@0.0.0.0~]# usermod -aG wheel atharv

[root@0.0.0.0~]#

[root@0.0.0.0~]#

[root@0.0.0.0~]#

[root@0.0.0.0~]#

[root@0.0.0.0~]# id atharv

uid=1002(atharv) gid=1002(dba) groups=1002(dba),10(wheel)

[root@0.0.0.0~]#

Remove the User from a Group in Linux

[root@0.0.0.0~]#

[root@0.0.0.0~]# gpasswd -d atharv wheel

Removing user atharv from group wheel

[root@0.0.0.0~]#

[root@0.0.0.0~]#

[root@0.0.0.0~]# id atharv

uid=1002(atharv) gid=1002(dba) groups=1002(dba)

[root@0.0.0.0~]#

[root@0.0.0.0~]#