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How to empty file contents w/o rm and touch

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# 1  
Old 07-18-2007
How to empty file contents w/o rm and touch
Hi all,

Can any one tell me how to empty the contents of a file in unix without using the following sequence : rm <file> ; touch <file>

is there any command in unix??
is it possible through shell scripting? If so, how?

-krishna
# 2  
Old 07-18-2007
Code:
echo "" > file 
cp /dev/null file
dd if=/dev/zero of=output.file bs=1 count=1

# 3  
Old 07-18-2007
Code:
cat /dev/null > your_file

lorcan
# 4  
Old 07-18-2007
and this,
Code:
>filename

# 5  
Old 07-18-2007
Quote:
Originally Posted by matrixmadhan
and this,
Code:
>filename



does this really work??? where and how to use this at the shell prompt??
# 6  
Old 07-18-2007
Quote:
Originally Posted by kris_kris
does this really work??? where and how to use this at the shell prompt??
I think this works only with ksh/bash shell not in csh. you just have to enter the command in your prompt.
# 7  
Old 07-18-2007
Here are other ways not mentioned yet:
Code:
: > file
cat file > file      ## Gives error message in ksh, but it works.
head file > file
tail file > file

Last edited by Shell_Life; 07-18-2007 at 09:47 AM.. Reason: Display comment of error message in 'cat'
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