vasya     ALL=(ALL)       NOPASSWD: /opt/lampp/lampp
или 
vasya     ALL=(ALL)       NOPASSWD: /opt/lampp/lampp, ALL

# sudo -l
Matching Defaults entries for root on this host:
    requiretty, env_reset, env_keep="COLORS DISPLAY HOSTNAME HISTSIZE INPUTRC KDEDIR LS_COLORS", env_keep+="MAIL PS1 PS2
    QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE", env_keep+="LC_COLLATE LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES",
    env_keep+="LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE", env_keep+="LC_TIME LC_ALL LANGUAGE LINGUAS
    _XKB_CHARSET XAUTHORITY", secure_path=/sbin\:/bin\:/usr/sbin\:/usr/bin

User root may run the following commands on this host:
    (ALL) ALL

$ sudo -l
Matching Defaults entries for cmd on this host:
    requiretty, env_reset, env_keep="COLORS DISPLAY HOSTNAME HISTSIZE INPUTRC KDEDIR LS_COLORS", env_keep+="MAIL PS1 PS2
    QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE", env_keep+="LC_COLLATE LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES",
    env_keep+="LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE", env_keep+="LC_TIME LC_ALL LANGUAGE LINGUAS
    _XKB_CHARSET XAUTHORITY", secure_path=/sbin\:/bin\:/usr/sbin\:/usr/bin

User cmd may run the following commands on this host:
    (ALL) NOPASSWD: ALL
    (ALL) ALL

cmd     ALL=(ALL)       NOPASSWD: ALL

$ sudo /opt/lampp/lampp start
[sudo] password for cmd: 

# cat /etc/pam.d/sudo
#%PAM-1.0
auth       include      system-auth
account    include      system-auth
password   include      system-auth
session    optional     pam_keyinit.so revoke
session    required     pam_limits.so

user   ALL = NOPASSWD: /path/to/command