Bash Upload Script

#!/bin/bash
UPLOAD_PATH="Backups"

if [[ -f '/root/dropbox.cfg' ]]; then
    echo 'It appears you have set an API Key for Dropbox already.'
    echo 'Using your configured API Key to proceed...'
    source /root/dropbox.cfg
else
    echo 'No existing API Key for Dropbox was found...'
    read -p 'Please provide an API Key to proceed ' api_key
    if [[ -z "$api_key" ]]; then
        echo "No key was provided. Exiting..."
        exit
    fi
    echo "DROPBOX_API_KEY=\"$api_key\"" >> /root/dropbox.cfg
    DROPBOX_API_KEY=$api_key
fi

read -p 'Please provide the path to the folder you wish to upload ' dest_path
if [[ -z "$dest_path" ]]; then
    echo "No path was provided. Exiting..."
    exit
else
    # Check if upload session exists
    if [[ -f "$dest_path/uploadsession.cfg" ]]; then
        echo "File exists using this upload session."
        source "$dest_path/uploadsession.cfg"
    # If it doesn't exist... create a session to be used
    else
        cd $dest_path
        touch uploadsession.cfg
        FIRSTFILE="$dest_path/uploadsession.cfg"
        curl -X POST https://content.dropboxapi.com/2/files/upload_session/start \
            --header "Authorization: Bearer $DROPBOX_API_KEY" \
            --header "Dropbox-API-Arg: {\"close\":false}" \
            --header "Content-Type: application/octet-stream" \
            --data-binary @${FIRSTFILE} >> /root/output.txt

        result=$(grep -oP '(?<="session_id": ")[^"]*' /root/output.txt)

        SESSION_ID=""
        IFS=':'
        for x in $result
        do 
            if [[ $x != "pid_upload_session" ]]; then
                SESSION_ID=$x
            fi
        done
        unset IFS

        echo "SESSION_ID=\"$SESSION_ID\"" >> "$dest_path/uploadsession.cfg"
        echo "Session ID = $SESSION_ID"
    fi

    # For each through each directory and folder, append to session
    for file in $dest_path/* $dest_path/**/*; do
        echo ${SESSION_ID};
        echo $file;
        curl -X POST https://content.dropboxapi.com/2/files/upload_session/append_v2 \
            --header "Authorization: Bearer $DROPBOX_API_KEY" \
            --header "Dropbox-API-Arg: {\"close\":false,\"cursor\":{\"offset\":0,\"session_id\":\"${SESSION_ID}\"}}" \
            --header "Content-Type: application/octet-stream" \
            --data-binary @${file} >> /root/output.txt
    done;

    # Finish Session
    curl -X POST https://api.dropboxapi.com/2/files/upload_session/finish_batch_v2 \
        --header "Authorization: Bearer $DROPBOX_API_KEY" \
        --header "Content-Type: application/json" \
        --data "{\"entries\":[{\"commit\":{\"autorename\":true,\"mode\":\"add\",\"mute\":false,\"path\":\"/${UPLOAD_PATH}\",\"strict_conflict\":false},\"cursor\":{\"offset\":0,\"session_id\":\"${SESSION_ID}\"}}]}"
fi<br />