 ,       .  
 su  ,      ,  
     root (   root).

  ,       su
(     ),    su (/bin/su)
  . (,  -    , 
    su,       , 
    su   .)

   su       
,   #.     (   -
,   )       : 
<CONTROL+D>    exit.   su   
  ,      .      
 PATH,         .  
,   root (     /sbin  /usr/sbin),
      (, /shin/service).  
 su - (    -1  --login)   
 root,        root.   root   
   ,    .    
     ,   PATH  
,     root,     /sbin  /usr/sbin.

 id        
,    :

$ id

uid=500(alex) gid=500 (alex) groups=500(alex)

$ su

Password:                                          ()

# id

uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys), ...

   su   -      
root,         -
.    ,     
    kill (. ).   su -  -
 root,    .   ,  
 su -       .

$ kill -15 4982

-bash: kill: (4982) - Operation not permitted     (  )

$ su - "kill -15 4982"

Password:                                          ()

$

, PATH  .      -
 PATH     root,   ,   -
   root  .     PATH
 root   ,   /sbin  /usr/sbin. -
       (  .  ..  PATH    :  -
  PATH).      "PATH:

   "  9.

 11,  :   397