How to create a new environment variable in UNIX…?

Question

How to create a new environment variable in unix and use it in a program??????

Answer 1

Depends on the shell. In bash, you can use:

export myvar=xyz

which will set the variable and make it available to other programs.

If you want to set it for one invocation of a program, you can use:

myvar=xyz ./myprog

This will have it set for the myprog process but not after it exits.