bash select loop


select - select from list.


select choice in `ls b*` quit
do
   echo $choice
   if [ "$choice" = quit ]
   then
     break
   fi
done 


Takes a list of strings and presents a numbered menu to user.

Takes numeric choice from user.

Places associated string in specified variable.

If invalid choice given, re-prompts user.

If user input is null, the list re-displayed.

Invalid choice will just generate new query prompt.

Requires break to exit out of loop.

Presented list is continuous, so avoid long lists, may scroll
off of screen.


set  - set command line arguments.

  set - normally used to list all set variables and functions.

set one "and to" tree for

for arg
do
   echo $arg
done 

Useful in functions 


return - used trigger return from functions and to set a 1 byte 
  return code of the function. 
return is only valid inside a function.

exit - used in trigger exit from script and to set a 1 byte return 
  code on exit. If used on command line, it will exit the current shell.
exit will exit script even if inside a function.