   setuid-.      
 setuid.      .

   

        .  
        ,   -
.        :  ,  -
       cd /  ,    
     .       .

          
    Is,     .   -
     Is  .   
  ,        .   -
      info    . (-
  ,  ,     Is   -d
("directory"  )  -1 ("long"  ).  d   , 
Is, ,  /home/alex/info  .)       
 ,  Is -1    .  (.)  
    :

$ who am i

jenny      pts/7   Aug 21 10:02

$ Is -Id /home/alex/info

drwx--x   2 alex     pubs         512 Aug 21 09:31 /home/alex/info

$ cd /home/alex/info

$ Is -1

.: Permission denied                 (  )

total 2                               ( 2)

    ,     ,  
    ,        
     .        -
 financial,       .        -
  notes,          cat:

$ Is -I memo.l memo.2 financial notes summary

-rw--   1 alex     pubs          34 Aug 21 09:31 financial

-rw-rr--   1 alex     pubs          21 Aug 21 09:31 memo.l

-rw-r--r   1 alex     pubs          21 Aug 21 09:32 memo.2

-rw-rr--   1 alex     pubs          30 Aug 21 09:32 notes

-rw-r--r--   1 alex     pubs          32 Aug 21 09:32 summary

$ cat financial

cat: cannot open financial             (  financial)

$ cat notes

  notes.

         info   -
 :

$ chmod o+r /home/alex/info

210                                               II.   Red Hat Linux