thanks for your help, but it's not so obvious
I perhaps was not clear enough but I need to script that !
to run an xterm at a specific directory, I tried (as script run by clicking on a directory into the file manager)
xterm & <---- this xterm will always be in my home directory
xterm -e "cd $dir" <---- this xterm flash and never wait for me
and to run a program hold by a specific using a script launched by root...
echo user: $USER
echo user: $USER <------- obviously this command wait the sub-shell logout ; please help
I really need someone's help on that because finding documentation on so precise points is a bit complex