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File already exists error while using '>' operator

 
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# 1  
Old 02-26-2009
File already exists error while using '>' operator
hi
i am using the below code

grep -v '^$' file1.lst >file1.lst

but it gives file1.lst already exists.
And i want to over rite on the same file

Whats the work around?
# 2  
Old 02-26-2009
Try:

Code:
grep -v '^$' file1.lst >| file1.lst

# 3  
Old 02-26-2009
Missing name for redirect.
i got this now

Missing name for redirect.
# 4  
Old 02-26-2009
OK,
so you're using (t)csh.
Try this:

Code:
grep -v '^$' file1.lst >! file1.lst

Notice that the space after the ! is important.
# 5  
Old 02-26-2009
yep i am using tcsh. sorry i didn't mention that before.

But the code does not work!!!

it deletes all the content..

i want to delete only the blank lines

file1.lst
abcd
abcdef
abgfhy

<end of file>

Code:
grep -v '^$' file1.lst >! file1.lst
cat file1.lst

nothing is present.
# 6  
Old 02-26-2009
I just noticed that you're using the same file for input and output! Of course it will remove all its content because the redirection is performed first.
You should use a temporary file like this:

Code:
grep -v '^$' file1.lst >! _temp_file_
mv _temp_file_ file1.lst

Or use a tool that supports in-place editing.
Last edited by radoulov; 02-26-2009 at 08:12 AM..
 
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