.xsession and .profile

[mikshaw]

$ help exec
exec: exec [-cl] [-a name] file [redirection ...]
    Exec FILE, replacing this shell with the specified program.
    If FILE is not specified, the redirections take effect in this
    shell.  If the first argument is `-l', then place a dash in the
    zeroth arg passed to FILE, as login does.  If the `-c' option
    is supplied, FILE is executed with a null environment.  The `-a'
    option means to make set argv[0] of the executed process to NAME.
    If the file cannot be executed and the shell is not interactive,
    then the shell exits, unless the shell option `execfail' is set.

I wasn't aware that you could use exec this way.  Thanks.