On Tuesday 04 September 2007 14:21, Scully, William P wrote:
>What's the best technique for trimming a file? IE: I have file
>"/var/log/toolarge". What's the fastest technique to discard
>
>- The first 10,000 records?
head -n 10000 /var/log/toolarge > /var/log/toolarge.$$ &&
mv /var/log/toolarge.$$ /var/log/toolarge
>- The last 10,000 records?
tail -n 10000 /var/log/toolarge > /var/log/toolarge.$$ &&
mv /var/log/toolarge.$$ /var/log/toolarge
>And as a bonus, since files are stream oriented, what's the fastest
>technique for finding out how many records are in the file?
wc -l /var/log/toolarge
All of these assume that your "record separator" is a newline character.
- MacK.
-----
Edmund R. MacKenty
Software Architect
Rocket Software, Inc.
Newton, MA USA
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