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Shell Programming and Scripting

Remove lines

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# 1  
Old 12-01-2010
Remove lines
i want to remove the records starting with abc or xyz in the file without redirecting the original file.

sample : file1.txt

abc1234
124234
2020202
3242342
xyz2342
2afafa

Expecting output
124234
2020202
3242342
2afafa
# 2  
Old 12-01-2010
Quote:
Originally Posted by Jairaj
i want to remove the records starting with abc or xyz in the file without redirecting the original file.
What does "redirecting the original file" mean?

Code:
egrep -v "^(abc|xyz)" < infile > outfile ; mv outfile infile

You won't find a solution for deleting lines which doesn't replace the original file. Even sed -i has to replace the original file, it just does it for you.
# 3  
Old 12-01-2010
Code:
 infile should not be redirected to outfile

# 4  
Old 12-01-2010
The mv would loose the inode of infile
instead:
Code:
cat outfile>infile
rm outfile

or you could just work with your outfile without taking car of infile if you don't want to modify it Smilie
# 5  
Old 12-01-2010
Thanks.
# 6  
Old 12-01-2010
Using sed and the -i option (not all sed support it, see 'man sed' for more infos)
Code:
sed -ri '/^(abc|xyz)/d' file1.txt

# 7  
Old 12-01-2010
Quote:
Originally Posted by tukuyomi
Using sed and the -i option (not all sed support it, see 'man sed' for more infos)
Code:
sed -ri '/^(abc|xyz)/d' file1.txt

Still replaces the original file, just does it for you, like I said above. This can have the side-effect of changing ownership of files when you run sed as a different user for example...
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