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Shell Tips & Tricks

Discussion in 'Unix' started by pradeep, Aug 10, 2009.

  1. pradeep

    pradeep Team Leader

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    Shell Tips & Tricks

    Create A Command Alias

    Most of us use 'ls -l' so, will it not be easier to have a smaller command to show us long listing, add the following line to ~/.bashrc
    Code:
    alias ll='ls -l'
    Using it
    Code:
    [root@pradeep ~]# ll
    total 264
    -rw------- 1 root   root     1221 May 21 21:57 anaconda-ks.cfg
    -rw-r--r-- 1 root   root     2063 Jul 20 12:21 content_passlimit.txt
    drwxr-xr-x 2 root   root     4096 Jul 20 16:09 dumps
    -rw-r--r-- 1 root   root    35779 May 21 21:56 install.log
    -rw-r--r-- 1 root   root     5142 May 21 21:56 install.log.syslog
    drwxr-xr-x 7 root   root     4096 Jun 24 16:23 json-1.2.0
    -rw-r--r-- 1 root   root    13286 Mar 15  2006 json-1.2.0.tgz
    -rw-r--r-- 1 root   root       17 Aug 10 13:30 lwp_cookies.dat
    -rw------- 1 root   root   141066 May 29 17:47 mbox
    -rw-r--r-- 1 root   root    11484 Jul  6 13:01 modify_printfile.pl
    -rw-rw-r-- 1 nagios nagios   4289 Mar 15  2006 package.xml
    drwxr-xr-x 2 root   root     4096 Jul 27 19:29 test
    drwxr-xr-x 2 root   root     4096 Jul 18 12:19 test1
    
    You may create as many aliases as you want. Please share any interesting aliases you create.

    Use Previous Command's Arguments

    Running a command with the same arguments used in the previous command, use '!*' to repeat all arguments or '!:2' to use the second argument. '!$' uses the last argument. Let's see a few examples.

    Code:
    [root@pradeep ~]# mkdir -p /tmp/pradeep/test/shell
    [root@pradeep ~]# cd !$
    cd /tmp/pradeep/test/shell
    [root@pradeep shell]# mkdir -p /tmp/pradeep/test2 /tmp/pradeep/test3
    [root@pradeep shell]# chmod -R 777 !:2 !:3
    chmod -R 777 /tmp/pradeep/test2 /tmp/pradeep/test3
    [root@pradeep shell]# touch a.txt b.txt
    [root@pradeep shell]# ls !*
    ls a.txt b.txt
    a.txt  b.txt
    [root@pradeep shell]# ls -l !*
    ls -l a.txt b.txt
    -rw-r--r-- 1 root root 0 Aug 10 13:54 a.txt
    -rw-r--r-- 1 root root 0 Aug 10 13:54 b.txt
    [root@pradeep shell]#
    
    Useful Bash Keystrokes

    Ctrl+U - Cuts everything to the left
    Ctrl+W - Cuts the word to the left
    Ctrl+Y - Pastes what's in the buffer
    Ctrl+A - Go to beginning of line
    Ctrl+E - Go to end of line
    Ctrl+R - Search command history

    Changing File Extensions

    Code:
    rename 's/.html$/.html.bak/' *.html
    This will change all .html files to html.bak

    Run a second command only if the first one is successfull

    Code:
    cd /tmp/pradeep/test/shell && tar xjvf /home/pradeep/songs.tar.bz
    This is usually used like this 'make && make install' while compiling softwares.
     
    nimesh likes this.
  2. shency

    shency New Member

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    Really interesting & useful
     
  3. adarshtp

    adarshtp New Member

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    nice one. Really helpful
     
  4. shabbir

    shabbir Administrator Staff Member

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  5. nimesh

    nimesh New Member

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    nice tips.
    Came to know some new commands.

    Thanks
     
  6. divengrabber

    divengrabber New Member

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    great info carry on.
     
  7. BukiBv

    BukiBv New Member

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    Code:
    Really good thanks
     
  8. King Falcon

    King Falcon New Member

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    thank you very much...
    this is really a good post...
     

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