 5.3.    
             

compress                  (  ,  gzip).

gunzip                   ,   gzip  compress,
     .

gzip                     .

zcat                      .

bzip2, bunzip2  bzcat    ,     ( gzip).

   ( ) ,    -
 .  tar (. 5.4)    . 
  .tar.gz  .tgz   ,   tar; 
     ,   Internet.

 5.4.  
    

tar                  .

,   . 5.5,     
. ,         C++,
   .

 5.5.   
    

apropos              man-.
whereis          ,     man-.
which            ,   .

 . 5.6  ,     .
      ,     ,  
    ,  .

 5.6.       
    

finger           ,   ,
      .

w                 ,   .
who              ,   .

,   . 5.7,     
  .

 5.7.    
    

mesg              ,   write  talk.

talk                
.

write              .

 5.  Linux                                                           189