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Satori80
Tux's lil' helper
Joined: 24 Feb 2004
Posts: 137
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 Posted: Thu Aug 18, 2005 6:37 pm Post subject: In need of a script, please help [solved] |
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I've tried to figure this out on my own but I give up. My messages file has been filled with BANDWIDTH_IN statements to the point where it's over 8 GB. I solved the problem but now I'd like to remove all those lines. At first I thought of grep and then sed but I can't find out how to make either do what I need. Every example I've found wants to remove duplicate lines or expressions from a line, not a whole line with a specific expression. 
I need a quick n' dirty script or command line to search for each line containing 'BANDWIDTH_IN', delete the entire line from the file, and then save the file back to /var/log/messages.
Last edited by Satori80 on Wed Aug 31, 2005 10:18 am; edited 1 time in total |
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R!tman
Veteran
Joined: 18 Dec 2003
Posts: 1303
Location: Zurich, Switzerland
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| Posted: Thu Aug 18, 2005 7:56 pm Post subject: |
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Maybe this works:
| Code: | | `cat file.you.want.to.change | sed -e '/BANDWIDTH_IN/D'` >> changed.file |
But try first, like this
| Code: | | cat file.you.want.to.change | sed -e '/BANDWIDTH_IN/D' | grep BANDWIDTH_IN |
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the_mgt
Apprentice
Joined: 05 Aug 2005
Posts: 259
Location: Germany, near Hannover
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| Posted: Thu Aug 18, 2005 9:05 pm Post subject: |
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eh, don't call me stupid, but have you tried | Code: |
cat /var/log/messages|grep -v 'BANDWIDTH_IN' > messages2 |
??
One thing about catting and grepping: NEVER ever cat from a file, pipe it through grep and write it back in the file you originally catted!!! This usually ends ugly!
Edited because my codeline was BS 
Last edited by the_mgt on Fri Aug 19, 2005 11:06 am; edited 2 times in total |
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Leo Lausren
Apprentice
Joined: 24 Feb 2004
Posts: 198
Location: Denmark
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| Posted: Fri Aug 19, 2005 6:32 am Post subject: |
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You could use sed | Code: | | sed -i '/BANDWIDTH_IN/d' /var/log/messages |
Best to run it with -e instead of -i first, to see if it does the right thing.
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Blog: common sense – nonsense |
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Satori80
Tux's lil' helper
Joined: 24 Feb 2004
Posts: 137
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| Posted: Fri Aug 19, 2005 8:34 am Post subject: |
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| R!tman wrote: | Maybe this works:
| Code: | | `cat file.you.want.to.change | sed -e '/BANDWIDTH_IN/D'` >> changed.file |
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Figured I'd try the first suggesiton first. I tried it on a test file and it worked as expected. It's working on a copy of my /var/log/messages file now, like so:
| Code: | | cat ./messages | sed -e '/BANDWIDTH/D' >> messages.2 && mv ./messages ./messages.old && mv messages.2 messages |
After I verify that the edited messages file looks like it should I'll archive the old one just in case.
Thanks very much to all of you for your help! I appreciate the advice given by each of you.
This is why I love Gentoo. Of all the distros I've tried over the years, the Gentoo userbase is the best in the Linux world. I don't care what some of the more elitist primadonna user groups think of Gentoo, you guys that take time out of your day to help someone with such trivial yet frustrating issues are the ones that make Gentoo as great as it is. |
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Earthwings
Bodhisattva
Joined: 14 Apr 2003
Posts: 7753
Location: Germany
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| Posted: Fri Aug 19, 2005 10:16 am Post subject: |
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| Leo Lausren wrote: | You could use sed | Code: | | sed -i '/BANDWIDTH_IN/d' /var/log/messages |
Best to run it with -e instead of -i first, to see if it does the right thing. |
That version is what I thought of as well. I made a test run with a random file (5.5 MB) and using in-place editing is several times slower than creating a new file. Makes sense of course as appending lines to a file is much quicker than deleting lines in the middle of a file. Therefore for a 8 GB file creating a temporary file is the way to go if space is not an issue.
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Leo Lausren
Apprentice
Joined: 24 Feb 2004
Posts: 198
Location: Denmark
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| Posted: Sat Aug 20, 2005 3:18 pm Post subject: |
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| Earthwings wrote: | | I made a test run with a random file (5.5 MB) and using in-place editing is several times slower than creating a new file. Makes sense of course as appending lines to a file is much quicker than deleting lines in the middle of a file. Therefore for a 8 GB file creating a temporary file is the way to go if space is not an issue. |
That make a lot of sense, and space is usually available these days.
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