Blog - Mohit Kumar Gupta

Ubuntu terminal command to switch to any drive

cd /media/<user_name>/<drive_name>;

Change Ubuntu 22.04 LTS desktop background to pure black

gsettings set org.gnome.desktop.background picture-uri "";

gsettings set org.gnome.desktop.background picture-uri-dark '';

gsettings reset org.gnome.desktop.background color-shading-type;

gsettings set org.gnome.desktop.background primary-color '#000000';

Notes: Install hplip in Ubuntu 22.04 along with plugin

Commands are as follows:

sudo apt update && sudo apt upgrade -y;

sudo apt install software-properties-common apt-transport-https -y;

sudo add-apt-repository ppa:kelebek333/hplip -y;

sudo apt-get update;

sudo apt-get install hplip hplip-gui -y;

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Next you need to install respective plugins

Check the version of hplip using command: dpkg -l hplip

Then, download corresponding plugin file & .asc file that matches with version from link https://www.openprinting.org/download/printdriver/auxfiles/HP/plugins/

Then in terminal, type: hp-plugin

Then follow the GUI screen to install plugin.

Notes: Ubuntu-Libreoffice: Uninstall default Libreoffice provided with Ubuntu & install of your own

Default Libreoffice that come with ubuntu don't have full version, like it don't have Libreoffice base. So one may need to uninstall default version & install full version of their own.

Terminal command to uninstall Libreoffice completely is as follows:

sudo apt-get update;sudo apt update

sudo apt-get -y remove --purge libreoffice* libexttextcat-data* && sudo apt-get -y autoremove

Terminal command to install Libreoffice full version after that is as follows

sudo add-apt-repository ppa:libreoffice

sudo apt install libreoffice

Verify installed version

libreoffice --version

Postgres-Ubuntu: Restore postgres database using pg_restore

Command is as follows:

pg_restore -U postgres -d <database name> -h localhost <backup_filename>.dump

Potgres-Ubuntu: Bash-script to take backup of list of databases

#!/bin/bash

declare -a arr=("db1" "db2" "db3" "db4" "db5" "db6")

for i in "${arr[@]}"

echo "$i"

pg_dump -U postgres -h localhost -Fc "$i" > ~/<folderPath>/"$i".dump

done

Notes: Inverter purchasing calculations for home

Take a list of items that will run in inverter like 2fans, 1 LED tubelight, 1 laptop, 2 LED TV, etc

Now calcullate sum of their power e.g 2*60+1*20+100+2*100 WH=440 WH

Now add 25% to above power sum e.g 440*125%=550WH

Then multiply it by power factor (most case it's 1/0.8) e.g 550/.08=687.5 WH

For every inverter has its own effeiency say 90%,80%, etc

Therefore, inverter power that has to be purchased = 687.5/90%=763.888 VA

Above is how to calculate inverter power that has to be purchased.

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Now comes how to choose battery power

Batter power (VA) = Home Load * Backup (hrs)/Battery Vold

= 687.5WH*2hr/12amp = 114.58

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This is how you do calculations for purchasing invertor

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