Plug in your Garmin, wait till it mounts. Then run the script. Happy good times.

Garmin2StravaSyncr.rb

require 'rest-client'
require 'highline/import'
require 'json'
require 'time'

@activityCount = 0
@uploadedCount = 0
@garminPath = "/Volumes/GARMIN/Garmin/Activities"

def startup()
    email = ask("Email: ")
    password = ask("Password: ") { |p| p.echo = false }

    if email && password
        puts "Authenticating with Strava..."
        begin
            response = RestClient.post "https://www.strava.com/api/v2/authentication/login", { email: email, password: password }.to_json, :content_type => :json, :accept => :json
        rescue Exception => e
            puts "Uh oh. It failed. #{e.message}"
        end

        if response.code == 200
            user = JSON.parse(response.body)
            puts "Your session token is: #{user["token"]}"
            
            if !File.exists?("#{@garminPath}/.stravaTrakt")
                File.open("#{@garminPath}/.stravaTrakt", "w")
            end

            dotTrakr = File.open("#{@garminPath}/.stravaTrakt", "r+")
            
            timeLastSaved = dotTrakr.read
            if timeLastSaved.length > 0
                timeLastSaved = Time.parse(timeLastSaved)
            end

            if !timeLastSaved.is_a?(Time)
                files = Dir.glob("#{@garminPath}/*.fit")
                @activityCount = files.length
                files.each { |f| uploadFile(user, f) }
            else
                files = Dir.glob("#{@garminPath}/*.fit").
                    select{|f| File.mtime(f) > timeLastSaved }
                @activityCount = files.length
                files.each{|f| uploadFile(user, f) }
            end
            dotTrakr.close

            if @activityCount == 0
                puts "No activities to sync"
            elsif @uploadedCount == @activityCount
                timeLastSaved = Time.now
                dotTrakr = File.open("#{@garminPath}/.stravaTrakt", "w+")
                dotTrakr.write(timeLastSaved).close
                puts "#{@activityCount} activities have been uploaded. Good work!"
            else
                puts "Some activities were skipped. Look into this"
            end
        end

    end
end

def uploadFile(user, activity)
    puts "Syncing Activity - #{File.basename(activity)} to Strava"
    payload = { token: user["token"], data: File.new(activity, 'rb').read, type: "fit"}

    begin
        response = RestClient.post "http://www.strava.com/api/v2/upload", payload
        if response.code == 200
            body = JSON.parse(response.body)
            puts "Great Success! Upload ID: #{body["upload_id"]}"
            @uploadedCount = @uploadedCount + 1
        end
    rescue Exception => e
        puts "Uh oh, something went wrong uploading the activity: #{e.message}"
    end

end

startup()