do_increment

UNIX+shell范例精解（第4版）代码

#!/bin/ksh
# Scriptname: do_increment
# Using the return Command)
function increment {
   typeset sum      # sum is a local variable.
   (( sum = $1 + 1 ))
   return $sum      # Return the value of sum to the script.
} 

print -n "The sum is "
increment 5         # Call the function increment and pass 5 as a
                    # parameter. 5 becomes $1 for the increment 
                    # function.
print $?            # The return value is stored in the ? variable
print $sum          # The variable "sum" was local to the 
                    # function, and is undefined in the main 
                    # script. Nothing is printed.