If you wish to turn the variables off, useinstead of set.
The Bourne shell syntax is different. To turn on the verbose flag, use:
-x turns on the echo flag.
You can also type them together:
It is not necessary to modify the program. You can enable variable tracing in Bourne shell scripts by typing the shell name and options on the command line:
Not all Bourne shells let you turn these variables off. If yours does, you can do it by using a plus sign instead of a minus sign: