Time Doctor is an application to track time. To uninstall Time Doctor on Ubuntu, run
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sudo /bin/bash -c 'apt purge sfproc; /bin/bash /opt/sfproc/uninstall' |
Ubuntu 18.04 MariaDB 10.2 Too many open files
On my computer running Ubuntu 18.04, MriaDB stopped working. PHP application i run on my computer failed with error
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SQLSTATE[42S02]: Base table or view not found: 1146 Table 'ok_test.feeds' doesn't exist (SQL: select * from `feeds` where `processed` = 0) |
Application can’t find the table. So i tried to login to MySQL and see if table is there or not. But i get error
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boby@sok-01:~$ mysql Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 2504 Server version: 10.2.30-MariaDB-1:10.2.30+maria~bionic-log mariadb.org binary distribution Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]> show databases; ERROR 1018 (HY000): Can't read dir of '.' (errno: 24 "Too many open files") MariaDB [(none)]> |
Next i checked if this is due to any MySQL upgrade. I found MySQL got updated today
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root@sok-01:~# grep mariadb /var/log/dpkg.log 2019-12-13 08:02:46 status triggers-pending mariadb-server-10.2:amd64 1:10.2.29+maria~bionic 2019-12-13 08:02:46 upgrade mariadb-common:all 1:10.2.29+maria~bionic 1:10.2.30+maria~bionic 2019-12-13 08:02:46 status half-configured mariadb-common:all 1:10.2.29+maria~bionic 2019-12-13 08:02:46 status unpacked mariadb-common:all 1:10.2.29+maria~bionic 2019-12-13 08:02:46 status half-installed mariadb-common:all 1:10.2.29+maria~bionic |
To fix this error, run
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systemctl edit mysql |
This wil open a text editor. Add following
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[Service] LimitNOFILE=8192 |
Save and quit the editor. Restart MaraDB with
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systemctl restart mysql |
MySQL will work properly now. systemctl edit mysql will create file /etc/systemd/system/mysql.service.d/override.conf
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root@sok-01:~# cat /etc/systemd/system/mysql.service.d/override.conf [Service] LimitNOFILE=8192 root@sok-01:~# |
Disable Native Notification on Google Chrome Ubuntu
On Ubuntu, Google chrome had a disable native notification option. On Chrome 78, this option is removed. But you still can manually enable it.
To enbale chrome notification, edit file
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gedit ~/.config/google-chrome/Local\ State |
Find
Replace with
Save and exit the file. Now restart google chrome.
Related Posts
Install NextCloud Desktop client on Ubuntu
To install NextCloud desktop client on Ubuntu, add PPA
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sudo add-apt-repository ppa:nextcloud-devs/client sudo apt-get update |
Now run
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sudo apt install nextcloud-client |
After install, start nextcloud client, you will be able to login with nextcloud server URL, user and password.
Linux KVM Bridge network on Ubuntu
On Ubuntu 18.04 server, first i get Ubuntu to use /etc/network/interface, by default Ubuntu 18.04 and newer use netplan.
First install ifdown
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apt install ifupdown -y |
Now you can configure your network interface by editing file
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vi /etc/network/interface |
Here is my network configuration on an OVH server.
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root@ns3048991:~# cat /etc/network/interfaces # interfaces(5) file used by ifup(8) and ifdown(8) # Include files from /etc/network/interfaces.d: source-directory /etc/network/interfaces.d auto eno3 iface eno3 inet static address 149.202.199.137 netmask 255.255.255.255 broadcast 149.202.199.137 gateway 149.202.199.254 dns-nameservers 8.8.8.8 8.8.4.4 root@ns3048991:~# |
To convert this interface to bridge network, do the following
1) Replace all occurance of “eno3” with “br0”
2) Add following lines
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bridge_ports eno3 bridge_stp off bridge_maxwait 5 |
In above, replace “eno3” with name of your physical interface.
Here is my final network configuration.
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root@ns3048991:~# cat /etc/network/interfaces # interfaces(5) file used by ifup(8) and ifdown(8) # Include files from /etc/network/interfaces.d: source-directory /etc/network/interfaces.d auto br0 iface br0 inet static address 149.202.199.137 netmask 255.255.255.255 broadcast 149.202.199.137 gateway 149.202.199.254 bridge_ports eno3 bridge_stp off bridge_maxwait 5 dns-nameservers 8.8.8.8 8.8.4.4 root@ns3048991:~# |
Install Xfce VNC remote desktop on Ubuntu
XFCE is a light weight desktop for Linux. XFCE + vnc allow you to setup remote desktop on a VPS or dedicated server located on a data center or cloud. You can connect to remote desktop using VNC client and work like it is local computer.
To instal XFCE run
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apt install -y xfce4 xfce4-goodies |
Next install vncserver
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apt install -y vnc4server |
It is bad idea to use root user for logging into desktop. Create a normal user to run desktop.
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useradd -m -s /bin/bash USERNAME_HERE |
It will be good to make this user an admin, so user can install software or update system.
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usermod -aG sudo USERNAME_HERE |
Now login as the user
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su - USERNAME_HERE |
Create a vnc password for this user.
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vncpasswd |
Create vnc startup file
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vi ~/.vnc/xstartup |
Add
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#!/bin/bash xrdb $HOME/.Xresources /usr/bin/vncconfig -nowin -display :1 & startxfce4 & |
Make it executable
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chmod 755 ~/.vnc/xstartup |
Now exit the user with “exit” command. You should be user “root” now.
Create service file
To auto start vncserver on boot, you need to create a service file.
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vi /etc/systemd/system/vncserver@.service |
Add
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[Unit] Description=VNC server startup script After=syslog.target network.target [Service] Type=forking User=USERNAME_HERE ExecStartPre=-/usr/bin/vncserver -kill :%i &> /dev/null ExecStart=/usr/bin/vncserver -depth 24 -geometry 1920x1080 :%i PIDFile=/home/USERNAME_HERE/.vnc/%H:%i.pid ExecStop=/usr/bin/vncserver -kill :%i [Install] WantedBy=multi-user.target |
Enable the service with
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systemctl enable vncserver@1 |
You can start/stop vncserver with
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systemctl stop vncserver@1 systemctl start vncserver@1 |
Now reboot the server. You should be able to connect to VNC server using SERVER_IP:1
Install HandBrake on Ubuntu 18.04
HandBreak is an OpenSource Video transcoder available from https://handbrake.fr. It can convert video to various format.
Latest version of Handbreak available in Ubuntu PPA. To install, enable Handbreak PPA
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add-apt-repository ppa:stebbins/handbrake-releases |
Install handbreak with
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apt install handbrake-gtk handbrake-cli |
Install Linux KVM on Ubuntu
Linux KVM is virtualisation software that allow you to create virtual machine under linux. To install on Ubuntu, run
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apt install -y qemu-kvm |
Install libvirtd, this allow you to easily create KVM virtual machines and allow remote connection from virt-manager GUI application.
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apt install -y libvirt-bin |
Enable and start libvirt
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systemctl enable libvirtd systemctl start libvirtd |
At this stage, you should be able to connect to KVM server form your computer using virt-manager.
You need to create a bridge network interface (“br0”), for this, follow instructions at Linux KVM Bridge network on Ubuntu.
Downloading ISO
Before you can setup any VM, you need to download ISO image for the OS. Here i downloaded ISO image for Ubuntu 19.04
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cd /var/lib/libvirt/images wget http://mirrors.piconets.webwerks.in/ubuntu-mirror/ubuntu-releases/19.04/ubuntu-19.04-live-server-amd64.iso |
Once downloaded, you should be able to select this ISO image in virt-manager when creating a VM.
See Linux KVM
Set default editor in Ubuntu
To set default editor in Ubuntu/Debian, run
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update-alternatives --config editor |
Install drivers on Ubuntu
To install drivers on Ubuntu using command line, run
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boby@sok-01:~$ sudo ubuntu-drivers devices == /sys/devices/pci0000:00/0000:00:01.1/0000:01:00.0 == modalias : pci:v000010DEd00001F82sv00001458sd00003FCBbc03sc00i00 vendor : NVIDIA Corporation driver : nvidia-driver-430 - distro non-free recommended driver : xserver-xorg-video-nouveau - distro free builtin boby@sok-01:~$ |
This list all drivers available for your hardware. You can install a driver with apt. In this cuase, i have 2 drivers available
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driver : nvidia-driver-430 - distro non-free recommended driver : xserver-xorg-video-nouveau - distro free builtin |
First driver is recommended by Ubuntu. To install, run
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apt install nvidia-driver-430 |
Install Driver using Software & Updates
Start software and updates application.
Click on Additional Drivers tab. You will see available drivers for your computer.
