reset_ssh.sh

#!/usr/bin/env bash

export USER="user"
export AUTHORIZED_KEYS="/home/$USER/.ssh/authorized_keys"
export KEY="public key" 

if [ "$1" == "-c" ];then
    echo "Creating user $USER"
    useradd -m -s /bin/bash $USER
fi

if [ ! -d "/home/$USER/.ssh" ];then 
    echo "Creating .ssh directory"
    mkdir "/home/$USER/.ssh" && chown $USER. "/home/$USER/.ssh"
fi

if [ ! -f "$AUTHORIZED_KEYS" ];then
    echo "Creating authorized_key file"
    touch "$AUTHORIZED_KEYS"
fi

if [ ! "$(grep ${KEY:9:100} $AUTHORIZED_KEYS)" ];then
    echo "Adding key to file"
    echo "$KEY" >> $AUTHORIZED_KEYS
    chmod 644 $AUTHORIZED_KEYS
    chown $USER. $AUTHORIZED_KEYS
fi