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sed working slow on big files

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# 1  
Old 02-15-2011
sed working slow on big files
HI Experts ,

I'm using the following code to remove spaces appearing at the end of the file.

Code:
 
sed "s/[ ]*$//g" <filename> > <new_filename>
 
mv <new_filename> <filename>

this is working fine for volumes upto 20-25 GB.

for the bigger files it is taking more time that it is required for the original file generation. :-)

I need to process files which will be 4-5 times bigger than this.

Please suggest a faster way.
# 2  
Old 02-15-2011
Not sure how much this buys you but: sed 's/ *$//' file > file1 seems like it should be a little faster.
# 3  
Old 02-16-2011
Thanks ! I can see slight saving on time.

but , is there any other way to do it ? any other command than sed ?
# 4  
Old 02-16-2011
Some process must write the file. Rewrite the process to omit the trailing spaces. Or pipe that process through the sed command as the file is written. As for faster, maybe perl:
Code:
perl -pe 's/ *$//'

. For real speed a custom c program is needed. But not writing the spaces to start with would be optimum.
This User Gave Thanks to Perderabo For This Post:
binlib
# 5  
Old 02-17-2011
Thank you!

you are right. one last question is cut faster than sed ?

to avoid spaces I have modified the code but getting 2 junk characters at the beginning of every line . want to use
Code:
cut -c 3- <filename>

to remove those.
# 6  
Old 02-18-2011
Quote:
to avoid spaces I have modified the code but getting 2 junk characters at the beginning of every line
What software is producing this file? Might be easier to fix at source?

Can you post say four sample lines with control codes visible. Just wondering if this not a proper unix text file.
Code:
sed -n l four_sample_lines.txt

Last edited by methyl; 02-18-2011 at 07:48 PM..
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