The importas program

importas replaces a literal with the value of an environment variable, then executes another program.

Interface

     importas [ -i | -D default ] [ -s ] [ -C | -c ] [ -n ] [ -d delim ] variable envvar prog...

• importas fetches the value of envvar in the environment. If neither the -D nor the -i option is given, and envvar is undefined, the null word is returned, which is incompatible with pre-1.06 versions of execline.
• importas then performs variable substitution on prog..., with variable as key and that string as value.
• importas then execs into the modified prog....

Options

• -D default : If envvar is undefined, and this option is not given, substitute zero word for variable instead of the empty word; and if it is given, substitute default instead. To emulate pre-1.06 behaviour, use -D "".
• -i : Insist. If envvar is undefined, importas will not do anything; instead, it will exit 100 with an error message. This has precedence over any -D option.
• Other options are used to control the substitution mechanism.