all-in-one/ubuntu/README.md

Useful shell command

• commands

// add a user to root group
$ visudo

# User privilege specification
root    ALL=(ALL:ALL) ALL
newuser ALL=(ALL:ALL)ALL

hold `ctrl` and press `x` to save and exit

// list all running process
$ ps aux

• run as root

user@host$ sudo su -

// prompt will show root login
root@host$ 

• add a user to a group

// create docker group
$ sudo groupadd docker

// add current user to group
$ sudo usermod -aG docker ${USER}

// restart to take effect

• change file permission

// excecute, read, write
$ chmod 777 filename

//

node version manager nvm

• For proper installing, using version manager for nodejs to install nodejs/npm
• use nvm
  • to avoid npm version conflict installation with nodejs
  • to install / switch to lower / newer version on any version ubuntu
• ubuntu 20.10 default support node 12
• ubuntu 19.10 default support node 10

// installation

$ curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.38.0/install.sh | bash

$ wget -qO- https://raw.githubusercontent.com/nvm-sh/nvm/v0.38.0/install.sh | bash

$ export NVM_DIR="$([ -z "${XDG_CONFIG_HOME-}" ] && printf %s "${HOME}/.nvm" || printf %s "${XDG_CONFIG_HOME}/nvm")"

# This loads nvm
$ [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh" 

// to install node version 10.10.0
$ nvm install 10.10.0

// remove node to solve conflicting version
$ sudo apt-get remove nodejs
$ sudo apt autoremove

• ssh id

$ ssh-keygen

// copy ssh public key to host .ssh/authorized_keys to allow passwordless ssh
$ ssh-copy-id -i abc@host

// alternatively, copy local .ssh/rsa_id.pub content into target server authorized_keys