 Is        . 
     ,      -
, Is       . ( , -
   ,     .)

cd:   

 cd ("change directory"   )    ,
    .   cd  . 6.8   
/home/alex/literature,     pwd.

$ cd /home/alex/literature
$ pwd

/home/alex/literature
$ cd
$ pwd
/home/alex

. 6.8.    cd

 cd       ,    
.    . 6.8       -
    .

   .      .
          ,   
  .              
.

   ,       .   
.      .    -
        cd     -
 .         
 .

 

 ,     ,  
 (startup files).          
 .        ,  
   (.  " "  )  
 stty ( )      .

         
  ,   .     
        .bash_profile (.  "-
 "  9).      , 
 ,       ,  
 Is ~a.     GUI-.    -
     ,    
       .

 6.   Linux 199