Shell Tips & Tricks - Part 2

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This is an article on Shell Tips & Tricks - Part 2 in Unix.
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.
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asha's Avatar, Join Date: Nov 2006
Go4Expert Member
Cool, the history one was really nice, it really helps me ;-)
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shabbir's Avatar, Join Date: Jul 2004
Go4Expert Founder
Nomination for Article of the month - Aug 2009 Started.
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shabbir's Avatar, Join Date: Jul 2004
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Vote for this article for Article of the month - August 2009