Update: Good catch by je44ery regarding Makefiles!! Original text follows...

Are you trying to merge a shell script with a Perl script or convert a shell script into a Perl script? That first line is pretty much not valid Perl. The ":" -- obvious separator used in shell PATH environment variables. And using \ to continue a line is also common in shell scripting (though I have no idea what you are continuing since the command appears to end there).

Perl scripts are not like shell scripts and you cannot mix and match like you are apparently trying to above.