UNIX COMMAND TO TRIM LOG FILES

[alana duvall_1]

I am looking for a command to trim log files that will keep the most recent entries (say the last 1000 lines). I tried using the tail command: tail -1000 logfile > logfile
But that did not work. It would only work for a number not larger than 200 lines.

Any suggestions?

Thanks

[James R. Ferguson · Accepted solution]

Hi Tony:

You can usw 'wc' to calculate the number of lines in your file, and then compute the line number from which you want to "save forward". For instance:

# LINES=`wc -l < myfile`
# let LINES=$LINES-100 # to remove the first 100 lines...
# sed -n $LINES,'$p' myfile > myfile.trimmed

...JRF...

[KapilRaj]

Hi ,

it's very easy.

#tail -l 1000 "logfile" > newlog
#cp newlog logfile

best of luck

kaps

[alana duvall_1]

Kaps

Thanks for your input. When I try your solution I only get a maximum of 229 lines in the trimmed file. The original file has over 8000 lines.

[Volker Borowski]

What about logrotate ?

http://www.freebsd.org/ports/sysutils.html#logrotate-3.5.2

Volker

[Rob Smith]

Hi, try this script:#!/usr/bin/sh
##
### Utility Menu to Manage the System Log
####
#####
syslog=/var/adm/syslog/syslog.log
## cp $syslog $syslog.orig

clear
print -n "

Manage the System Log: $syslog

1. View --> Read the System Log File
2. Count --> Tally the number of ERRORS and WARNINING
3. Trim --> Empty the Log File
4. Display --> Show Size of the System Log File
5. Exit --> Exit this Program

Select from the menu: "
read pick

case "$pick" in
1| [Vv] ) tail -200 $syslog | more ; manage ;;
2| [Cc] ) errors=$(grep -c -e ERROR $syslog)
warns=$(grep -c -e WARNING $syslog)
((total=errors+warns))
print "There are $total Errors or Warnings in the $syslog" ;;
3| [Tt] ) print "Clearing the $syslog"
cp -p $syslog /var/adm/syslog/syslog.log.$(date +%m%d%y)
> $syslog ;;
4| [Dd] ) ls -l /var/adm/syslog/syslog.log | awk '{print $5}' ;;

5| [Ee] ) exit ;;
esac
exit

Hope this helps.

Rob

[alana duvall_1]

JRF

Thank you
I have not used the sed command before. It looks like it will take care of what I need
Thanks Again