linux_new_user_guide.md

Guide: Adding a New Linux User and Customizing Environment

This guide walks through the process of adding a new user to a Linux system, setting up SSH access, installing Miniconda, and customizing the bash prompt.

1. Adding a New User

1. Log in as root or a user with sudo privileges.

2. Create the new user without a password:

   sudo adduser --disabled-password --gecos "" vladimir_albrekht

   Replace username with the desired username.

3. If the home directory already exists, adjust ownership:

   sudo chown -R vladimir_albrekht:vladimir_albrekht /home/vladimir_albrekht
   sudo chmod 755 /home/vladimir_albrekht

2. Setting Up SSH Access

1. Switch to the new user:

   sudo su - vladimir_albrekht

2. Create and configure the SSH directory:

   mkdir -p ~/.ssh
   chmod 700 ~/.ssh
   touch ~/.ssh/authorized_keys
   chmod 600 ~/.ssh/authorized_keys

3. Add your public SSH key to ~/.ssh/authorized_keys.

4. Exit the new user's shell:

   exit

5. Update your local SSH config file (~/.ssh/config):

   Host NewUserHost
     HostName your_server_ip
     User vladimir_albrekht
   

3. Installing Miniconda

1. Switch to the new user:

   sudo su - vladimir_albrekht

2. Download and install Miniconda:

   mkdir -p ~/miniconda3
   wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -O ~/miniconda3/miniconda.sh
   bash ~/miniconda3/miniconda.sh -b -u -p ~/miniconda3
   rm ~/miniconda3/miniconda.sh

3. Initialize Miniconda:

   ~/miniconda3/bin/conda init bash

4. Reload the bash configuration:

   source ~/.bashrc

4. Customizing the Bash Prompt

1. Open the .bashrc file:

   nano ~/.bashrc

2. Add the following code at the end of the file:

   # Conda environment display in prompt
   conda_env() {
       if [ -n "$CONDA_DEFAULT_ENV" ]; then
           echo "($CONDA_DEFAULT_ENV) "
       fi
   }
   
   # Set the prompt
   PS1='$(conda_env)\[\033[01;34m\]\w\[\033[00m\]\$ '

3. Save and exit the file (Ctrl+X, then Y, then Enter).

4. Reload the bash configuration:

   source ~/.bashrc

Your new prompt will now display the active conda environment (if any) and the current directory in blue, followed by a $ sign:

(base) ~/projects$ 

Optional: Including Conda Version in Prompt

If you want to include the conda version in your prompt, replace the PS1 line in step 2 of the "Customizing the Bash Prompt" section with:

PS1='$(conda_env)(conda $(conda --version | cut -f2 -d" ")) \[\033[01;34m\]\w\[\033[00m\]\$ '

This will result in a prompt like:

(base) (conda 23.7.1) ~/projects$ 

Remember to source your .bashrc file or log out and log back in for changes to take effect.

5. Adding Custom Aliases and Functions

You can add custom aliases and functions to your .bashrc file to create shortcuts for frequently used commands. Here's how to do it:

1. Open your .bashrc file:

   nano ~/.bashrc

2. Add the following lines at the end of the file:

   # Custom aliases
   alias n='nvidia-smi'
   alias c='cd ..'
   
   # Custom functions
   function mkcd() {
       mkdir -p "$1" && cd "$1"
   }

3. Save and exit the file (Ctrl+X, then Y, then Enter).

4. Reload your .bashrc file:

   source ~/.bashrc

Now you have the following shortcuts:

• Type n to run nvidia-smi
• Type c to go up one directory (equivalent to cd ..)
• Use mkcd directory_name to create a new directory and immediately change into it

You can add more aliases and functions as needed. Here are some examples:

# More alias examples
alias update='sudo apt update && sudo apt upgrade'
alias ll='ls -alF'
alias py='python3'

# More function examples
function extract() {
    if [ -f $1 ] ; then
        case $1 in
            *.tar.bz2)   tar xjf $1     ;;
            *.tar.gz)    tar xzf $1     ;;
            *.bz2)       bunzip2 $1     ;;
            *.rar)       unrar e $1     ;;
            *.gz)        gunzip $1      ;;
            *.tar)       tar xf $1      ;;
            *.tbz2)      tar xjf $1     ;;
            *.tgz)       tar xzf $1     ;;
            *.zip)       unzip $1       ;;
            *.Z)         uncompress $1  ;;
            *.7z)        7z x $1        ;;
            *)           echo "'$1' cannot be extracted via extract()" ;;
        esac
    else
        echo "'$1' is not a valid file"
    fi
}

Remember to source your .bashrc file or log out and log back in for changes to take effect.

These customizations can significantly speed up your command-line workflow by reducing the amount of typing needed for common tasks.