/dev/pts/1.        who am i 
    Is,    ,  -
   echo   /dev/pts/1,    -
   :

$ who am i

bravo.example.com'alex     pts/1    May 10 13:03

$ Is /dev/pts

0   1   2

$ echo   > /dev/pts/1

 

/dev/zero.          (-
,    ASCII).    (,  , .
 "swap"    )      
 ,   .  od  
 :

$ dd ifs/dev/zero of=zeros bs=1024 count=10

10+0 records in

10+0 records out

$ Is -1 zeros

-rw-rw-r    1 alex     alex        10240 Dec 3 20:26 zeros

$ od ~c zeros

0000000 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0

*

0024000

  ,      /dev/null,    -
 /dev/zero,       ,   :

$  /dev/zero bigzero

: writing 'bigzero': No space left on device
( 'bigzero':    )
$ rm bigzero

/etc/aliases.     ( sendmail)  
 (aliases) .    ,   -
 .       " 
"  20.

/etc/at.allow, /ete/at.deny, /etc/cron. allow  /ete/cron.deny.   
   at  .   at. allow   -
,     at.  cron. allow  
     cron.  at. deny  cron. deny  -
,      .  
 Red Hat   at. deny    at. allow 
  at;   cron. allow  cron. deny   -
 cron.     at ,  -
,   at. allow  at. deny.    
cron ,  ,   cron. allow    root.
.  " "  16.

448                                       IV.  