Hi, I would like to execute an external prog with this command line : "emmix < file.in" but emmix is not in %path% (windowsxp) so : "set path=%path%;%emmixPath%" "emmix < file.in" i use the system() function. system("set path=%path%;%emmixPath%"); system("emmix < file.in"); it doesnt work ! is it possible to execute 2 commands with the system function like system("set path=%path%;%emmixPath% ; emmix < file.in") ? this line doesnt work too, it set path with "=%path%;%emmixPath% ; emmix < file.in" !