How to call a program from a program

I've written some basic programs such as foward x, left x, turn around. How do I properly call these programs from within my main program? calling them directly I get an error. Do I need to have a main() function? Is there a startup function?

Please post the code you've been using.

If this helps.. I have a "forward" program..

args = {...}
if args[1] == nil then
print("Moving foward")
turtle.forward()
else
print("Moving foward "..args[1])
for i=1,args[1] do
  turtle.forward()
end
end

I also have a back, down, up, dig down etc..
I want to call this indivuaully as needed but also use them in a main program which I tried.. this

Name Mine

digDownandmove 1
digfrontandmove 3
back
digup
digdownandmove
back

However I get an error: bios:339 [string "mine"]:1: '=' expected

A program you make won't act the same as something you input into the shell. To run a program from another, you use shell.run("programName",arguments)

Try using this instead of the first line:

shell.run("digDownandmove",1)

And then use similar code for the other programs.

You may want to look into functions as well.

You can also put the whole string in the first argument of shell.run, like so:

shell.run("digDownandmove 1")

Thank you both!