In this tutorial, How to enable two-factor authentication (2FA) for SSH logins.  Install the Google Authenticator on AlmaLinux sudo dnf install epel-release -y sudo dnf install google-authenticator qrencode qrencode-libs -y After install completes, I will create a new secret key in ~/.ssh directory Run command as follows google-authenticator -s ~/.ssh/google_authenticator The output terminal as below [root@DevopsRoles ~]# google-authenticator -s ~/.ssh/google_authenticator Do you want authentication tokens to be time-based (y/n) y Warning: pasting the following URL into your browser exposes the OTP secret to Google:   https://www.google.com/chart?chs=200x200&chld=M|0&cht=qr&chl=otpauth://totp/[email protected]%3Fsecret%3DDXFSMCJ42VQ7FPMS2VAJ3CIJIE%26issuer%3DDevopsRoles.com Your new secret key is: DXFSMCJ42VQ7FPMS2VAJ3CIJIE Your verification code is 222214 Your emergency scratch codes are:   36072722   12212187   31577834   31344084   92578576 Do you want me to update y

 In this tutorial, How to  run a Speedtest from your command line. The requirement Nodejs version > 8+.    Install speed test command line [vagrant@localhost ~]$ wget https://nodejs.org/dist/v14.15.4/node-v14.15.4.tar.gz [vagrant@localhost ~]$ tar xvf node-v14.15.4.tar.gz [vagrant@localhost ~]$ cd node-v14.15.4/ [vagrant@localhost node-v14.15.4]$ sudo ./configure [vagrant@localhost node-v14.15.4]$ sudo make [vagrant@localhost node-v14.15.4]$ sudo make install Use NPM install speed test [vagrant@localhost ~]$ sudo npm install --global speed-test  The result, Install speed-test [vagrant@localhost node-v14.15.4]$ sudo npm install --global speed-test /usr/local/bin/speed-test -> /usr/local/lib/node_modules/speed-test/cli.js + [email protected] updated 2 packages in 10.4s [vagrant@localhost node-v14.15.4]$ Usage speed-test [vagrant@localhost node-v14.15.4]$ speed-test --help   Test your internet connection speed and ping using speedtest.net from the CLI   Usage     $ speed-test   Optio

 In this tutorial, How to connect to WiFi ubuntu server on Rasberry Pi  4. Today, I buy Rasberry PI 4 new and install ubuntu 20.04 LTS. root@ubuntu:~# cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=20.04 DISTRIB_CODENAME=focal DISTRIB_DESCRIPTION="Ubuntu 20.04.1 LTS" root@ubuntu:~#  after finish, Rasberry Pi 4 no identify ip address of wilfi. :D.  Rasberry Pi 4 can't connect to WiFi ubuntu server [fixed] The first, check network interface your system. ll -la /sys/class/net/ Create new file config for wifi " /etc/netplan/wlan.yaml" apply configure and reboot netplan apply The result, as below root@ubuntu:~# ll -la /sys/class/net/ total 0 drwxr-xr-x  2 root root 0 Jan  1  1970 ./ drwxr-xr-x 74 root root 0 Jan  1  1970 ../ lrwxrwxrwx  1 root root 0 Jan  1  1970 eth0 -> ../../devices/platform/scb/fd580000.ethernet/net/eth0/ lrwxrwxrwx  1 root root 0 Jan  1  1970 lo -> ../../devices/virtual/net/lo/ lrwxrwxrwx  1 root root 0 Apr  1  2020 wlan0 -> ../.

In this tutorial, How to change the order of columns in the output of `uniq -c` command. I use read the file and show the unique Name from the file. How many time this name of the file? The content of file as example below [HuuPV@DevopsRoles ~]$ cat devopsroles.txt  huu huu phan van dev devopsroles dev huu huu I use awk, sort uniq command to read file and show the unique Name as example below [HuuPV@DevopsRoles ~]$ cat devopsroles.txt | awk '{print $1}' | sort | uniq -c | sort -nr       4 huu       2 dev       1 van       1 phan       1 devopsroles Now, How to change the order of columns in the output of file [HuuPV@DevopsRoles ~]$ cat devopsroles.txt | awk '{print $1}' | sort | uniq -c | sort -nr | awk '{ print $2,$1}' huu 4 dev 2 van 1 phan 1 devopsroles 1 [HuuPV@DevopsRoles ~]$ cat devopsroles.txt | awk '{print $1}' | sort | uniq -c | sort -nr | awk '{ print $1,$2}' 4 huu 2 dev 1 van 1 phan 1 devopsroles Conclusion  How to change the order of

Today, I have not mount usb external USB into Fedora 32. External USB drive is NTFS formatted.  I will installed ntfs-3g  package for fedora as below: sudo dnf install ntfs-3g ntfsprogs The first, check your device address , you run this command as below sudo fdisk -l # or lsblk -f The output device is /dev/sd XY (where X and Y are the letter of the drive's device and Y is the partition number).  So in my case /dev/sdc1 is usb  drive external NTFS formatted. you will replace "device name" with your windows partition ( ex: /dev/sdb1 or /dev/sdd1 .v.v) How to do fix it Now, Open your terminal and run command to fix a Corrupted Windows NTFS Filesystem with Linux [HuuPV@DevopsRoles ~]$ sudo ntfsfix /dev/sdc1 Mounting volume... $MFTMirr does not match $MFT (record 0). FAILED Attempting to correct errors... Processing $MFT and $MFTMirr... Reading $MFT... OK Reading $MFTMirr... OK Comparing $MFTMirr to $MFT... FAILED Correcting differences in $MFTMirr record 0...OK Processing

 In this tutorial, I have fix semanage command not found in Centos 8. Semanage is an SELinux (Security-Enhanced Linux) management tool  Error semanage command not found in Centos 8  bash: semanage: command not found I use yum command  [root@DevopsRoles ~]# yum provides /usr/sbin/semanage The terminal output as below: Last metadata expiration check: 1:04:49 ago on Sun 09 Aug 2020 12:50:49 PM UTC. policycoreutils-python-utils-2.9-9.el8.noarch : SELinux policy core python utilities Repo        : BaseOS Matched from: Filename    : /usr/sbin/semanage It's missing policycoreutils-python-utils package in Centos 8. Now, I install package it. [root@DevopsRoles ~]# yum install policycoreutils-python-utils Once the install complete, you try semanage command on Centos 8. # man semanage OR # semanage --help I hope this helps you! have a nice day!

 In this tutorial, How to upgarde php version on Centos 7. My Server have installed php71. I will upgrade php to version php74 Type the following command to check the current version PHP. # php -v # yum list installed | grep -i php Now, Let go upgade php version to php74 If your has no remi repo, then Turn on Remi repo: # yum install http://rpms.remirepo.net/enterprise/remi-release-7.rpm Install yum-utils package # yum install yum-utils If you want to install PHP 7.1, PHP 7.2, PHP 7.3 or PHP 7.4 on CentOS 7. Just enable it as below # yum-config-manager --enable remi-php71 # yum-config-manager --enable remi-php72  # yum-config-manager --enable remi-php73 # yum-config-manager --enable remi-php74 For exmaple, I will chose php74 in this tutorial. # yum-config-manager --enable remi-php74 Update Centos 7  server. # yum update Checking version one more time # php -v You have update php version to php74 running on Centos 7 Server.

In this tutorial, I will use YUM command to install specific version of Package. Step 1: How to list the available package version in our repository. Syntax: # yum --showduplicate list [package_name] For Example [root@devopsroles ~]# yum --showduplicate list nodejs Remi's Modular repository for Enterprise Linux 8 - x86_64                                                                                                                          207 kB/s | 539 kB     00:02 Safe Remi's RPM repository for Enterprise Linux 8 - x86_64                                                                                                                         388 kB/s | 1.4 MB     00:03 Available Packages nodejs .x86_64                                                                            1:10.19.0-1.module_el8.1.0+277+2bccb1a9                                                                            AppStream Step 2: Install the specific version of the nodejs packag

In this tutorial, How to resolve Error: rpmdb open failed Error In CentOS. I was testing on nginx web server in Centos 7 VM Linode . Unfortunaely, I have install new package with yum command , I got this error message: error: rpmdb: BDB0113 Thread/process 3050/139803232012096 failed: BDB1507 Thread died in Berkeley DB library error: db5 error(-30973) from dbenv->failchk: BDB0087 DB_RUNRECOVERY: Fatal error, run database recovery error: cannot open Packages index using db5 -  (-30973) error: cannot open Packages database in /var/lib/rpm CRITICAL:yum.main: Error: rpmdb open failed It seemes like YUM broke down. I have not run any yum command. Solve problem, just do the following steps.   First backup the rpm database using command as root user: # mv /var/lib/rpm/__db* /tmp Run the following command: # yum clean all # yum update Clean backup # rm -i /tmp/__db* I hope this helps you.

Your system to many old kernels version. How to remove old kernels in CentOS , RHEL and Fedora . For example, I have three kernel,and to keep two kernel on system. How to do it! To check kernel release on centos/RHEL and Fedora [huupv@huupv ~]$ uname -sr The output kernel release as below: Linux 4.15.15-300.fc27.x86_64 Checking installed kernel [huupv@huupv ~]$ rpm -q kernel The output three kernel as below: kernel-4.15.13-300.fc27.x86_64 kernel-4.15.14-300.fc27.x86_64 kernel-4.15.15-300.fc27.x86_64 Delete / Remove Old Kernels To install yum-utils [root@huupv huupv]# yum install yum-utils The output as below: Last metadata expiration check: 2:54:35 ago on Sat 14 Apr 2018 07:14:37 PM +07. Dependencies resolved. ================================================================================  Package                  Arch        Version                 Repository   Size ================================================================================ Installi