usr/local/bin/gcc LIB=/tmp/perlmodules PREFIX=/tmp/perlmodules gcc: LIB=/tmp/perlmodules: No such file or directory gcc: PREFIX=/tmp/perlmodules: No such file or directory gcc: no input files. But I create this dir /tmp/perlmodules in this Solaris Box. so some things wrong ?

Really? Did you create directories LIB=/tmp/perlmodules and PREFIX=/tmp/perlmodules? That is, in the directory you run gcc from, you have subdirectories LIB= and PREFIX=, each with a subdirectory tmp, who in turn have a subdirectory perlmodules?

My guess is that you have your shell foo wrong. If you want to set environment variables specifically for the duration of one command, the setting goes in front of the command and its arguments.

But that's not a Perl problem. Read your shells manual page. (And if you indeed have created those oddly named directories, you have a gcc problem - which isn't Perl either).