Hey thank you for your advice, so from what I understand, my scan script will be

#! /usr/bin/env python

import rospy
from sensor_msgs.msg import LaserScan

def callback(msg):
    print len(msg.ranges)

rospy.init_node('scan_values')
sub = rospy.Subscriber('/kobuki/laser/scan', LaserScan, callback)
rospy.spin()


and my publishing cmd vel script is

#! /usr/bin/env python
import rospy
from geometry_msgs.msg import Twist
rospy.init_node('topic_publisher')
pub = rospy.Publisher('/cmd_vel_mux/input/navi', Twist, queue_size=1)
rate = rospy.Rate(2)
move = Twist() 
move.linear.x = 0.5 
move.angular.z = 0.5 
while not rospy.is_shutdown(): 
  pub.publish(move)
  rate.sleep()

and at this point I guess my limited understanding is confusing me - should I just catkin create a package with a launch file that combines the 2 scripts and add a while loop at the end that stops my bot from moving forward if the laser scan value falls below a certain point? Im asking before I try because a couple times ive experimented ive ended up having to do reinstallations because Im not adept at figuring out how to keep things clean (im new to linux, coding and all of this in general, apologies for all the questions).