Frequently needed but always forgotten.
Bash
# check folder size
du -h --max-depth=1# list files in directory starts with z
ls z*# list files starts with z and
# second character must be c or d
ls z[cd]*# search for a keyword within all the files
# in the directory and all its subdirectory
grep -rnw . -e 'pattern'# substring 'pot' from 'hippopotamus'
echo 'hippopotamus'|cut -c6-8# file fruits.txt has 5lines, command to print line 2 to 4
# pear
# apple
# banana
# orange
# strawberry
sed -n -e '2,4p' fruits.txt# if the path or filename has no spaces in it
find .|grep some_pattern|xargs rm -rf
# if the path or filename has space in it
find .|grep some_pattern|xargs -I @ sh -c 'rm -rf "@"'
Vim
# vimrc config
cd ~
echo 'set tabstop=2'>>.vimrc
echo 'set shiftwidth=2'>>.vimrc
echo 'filetype indent on'>>.vimrc
echo 'set hlsearch'>>.vimrc# vim editor
shift + v = select line
ctrl + v = select char by char
# after selection
shift + i = insert char
shift + u = convert selection to uppercase
u = convert selection to lowercase
Virtualbox
Install Virtualbox guest additions. Tested working in Linux Mint 20 Ulyana. Ran properly for a while for Elementary OS 5.1.5 Hera, then crash. Did not manage to get it working with Ubuntu Mate 20.04, maybe I missed something.
sudo apt update
sudo apt upgrade -y
sudo apt install virtualbox-guest-x11 -y
After setting up the shared folder, run the command below to grant permission to the folder.
sudo adduser $USER vboxsfCrontab
#run VNC server at display 1 after reboot using ubuntu user
@reboot su ubuntu -c 'vncserver :1'Run script at server reboot with different user
