Rasberry Pi 4 can't connect to WiFi ubuntu server [fixed]

 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 -> ../.

How to change the order of columns in the output

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

ntfsfix fix NTFS not mount from Linux

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

Fix semanage command not found in Centos 8

 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!

How to Upgrade php version on Centos 7

 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 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.

How to Install Specific Version of Package use YUM

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

How to resolve Error: rpmdb open failed In CentOS

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.

Remove old kernels in CentOS, RHEL and Fedora

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

How to install aide centos

Introduction In this tutorial, we will explore how to install and configure AIDE (Advanced Intrusion Detection Environment) on CentOS. AIDE is a powerful tool designed for monitoring changes to files on the system, helping you detect unauthorized access and modifications.  Ideal for system administrators and security professionals, this guide will provide step-by-step instructions to ensure a successful setup of AIDE on your CentOS system. By the end of this tutorial, you will have a robust intrusion detection system in place, capable of providing detailed reports about the integrity of your files and system security. What does Aide mean AIDE is one of the most popular tools for monitoring the server changes in a LINUX based system.  It call as Advanced Intrusion Detection Environment. Install AIDE on Centos $ sudo yum install aide Check AIDE Version on your system $ sudo aide -v Configure AIDE $ sudo cp /etc/aide.conf /etc/aide.conf_BK Add lines not check /tmp and /pro

After install setup Fedora 30

In this tutorial, Things to Do After Fresh Installation Fedora 30. Let do it! TO DO 1. Update your Fedora Always keep your system updated to the latest version of packages. $ sudo dnf update 2. Change the hostname $ sudo hostnamectl status # view current hostname $ sudo hostnamectl set-hostname --static "VivoS15" # set up new hostname 3. DNF tweak edit /etc/dnf/dnf.conf file $ sudo cp /etc/dnf/dnf.conf /etc/dnf/dnf.conf_ORIG [huupv@localhost ~]$ cat /etc/dnf/dnf.conf [main] gpgcheck=1 installonly_limit=3 clean_requirements_on_remove=True fastestmirror=true deltarpm=true 4. Install RPM fusion repository $ sudo dnf update --refresh $ sudo dnf install$(rpm -E %fedora).noarch.rpm $ sudo dnf install$(rpm -E %fedora).noarch.rpm 5. Player and codecs $ sudo dnf install youtube-dl vlc $ sudo dnf in