Shell Tips & Tricks - Part 2

Discussion in 'Unix' started by pradeep, Aug 20, 2009.

  1. pradeep

    pradeep Team Leader

    Joined:
    Apr 4, 2005
    Messages:
    1,645
    Likes Received:
    87
    Trophy Points:
    0
    Occupation:
    Programmer
    Location:
    Kolkata, India
    Home Page:
    http://blog.pradeep.net.in
    Part I - Shell Tips & Tricks

    Clear and Disable Bash History



    Use the Bash inbuilt history command:

    Code:
    history -c
    To prevent writing of your Bash history to the history when you log out:

    Code:
    unset HISTFILE

    Ampersand (Background Jobs)



    & is a inbuild operator to fork processes.

    "If a command is terminated by the control operator &, the shell executes the command in the background in a subshell"​

    Code:
    [root@pradeep test]# sleep 60 &
    [1] 32739
    
    The process id is stored in a special variable $!
    Code:
    [root@pradeep test]# echo $!
    32739
    
    List all background jobs
    Code:
    [root@pradeep test]# jobs
    [1]+  Running                 sleep 60 &
    
    Killing any background job
    Code:
    [root@pradeep test]# kill %1
    [1]+  Terminated              sleep 60
    

    Search An Replace in vi



    Open a text file in vi/vim and goto command mode by pressing ECS and then ':', the search and replace command will be like,

    Code:
    %s/oldString/NewString/g
    You can also mention which lines should be affected by this, %s means all lines.

    Code:
    5,10 s/oldString/NewString/g
    This will tell vi to make do replacing in lines 5 to 10. You may also use regex in your search expression.
     
  2. asha

    asha New Member

    Joined:
    Nov 9, 2006
    Messages:
    44
    Likes Received:
    2
    Trophy Points:
    0
    Occupation:
    Homemaker
    Location:
    Kolkata
    Home Page:
    http://whatanindianrecipe.com
    Cool, the history one was really nice, it really helps me ;-)
     
  3. shabbir

    shabbir Administrator Staff Member

    Joined:
    Jul 12, 2004
    Messages:
    15,336
    Likes Received:
    377
    Trophy Points:
    83
  4. shabbir

    shabbir Administrator Staff Member

    Joined:
    Jul 12, 2004
    Messages:
    15,336
    Likes Received:
    377
    Trophy Points:
    83

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice