Shell Programming and Scripting

Hey everyone, I'm fairly new to both unix and shell scripts. Right now I have a script that I can run in one folder (if a certain text file is there, do one thing, if it's not, do something else). I want to modify this to run in multiple directories. My setup is: a company directory, and within it directory c1, c2, c3, etc. I assume that I have to use some recursive call or looping to tell the script to run on every directory, but I haven't been able to figure it out from searching online. Thanks!

Code:

cd directory
find . -print -type d |
while read dirname do
   cd $dirname
   # run your code at this point
   cd -
done

Thanks, this is exactly what I was looking for.

edit: This is the current state of my code, and it almost does what I'm looking for--how can I make the loop exclude the root directory companies? I only want this to happen in the immediate subfolders.

Code:

cd companies
find . -type d -print |
while read dirname 
do
  cd $dirname
  if [ -f "changes.txt" ]; then
     #some code
  else
      #some other code
  fi
  cd -
done