clear_log.sh

#!/bin/bash 
#clear tomcat logs

#log size (1M bytes)，if lt, clear 
LOG_FILE_SIZE=1024000 

#define logs location 
logs=(/usr/local/tomcat/logs/catalina.out) 

for ff in "${logs[@]}"; 
do 

#file size 
size=0 
if [ -f $ff ] 
then 
#get file size 
size=`ls -l $ff |awk '{print $5}'` 
fi 

#judge
if [ "$size"0 -gt "$LOG_FILE_SIZE"0 ] 
then 
echo start clear: "$ff" , size= "$size" 
true > $ff 
fi 

done 

#finish clear 
echo clear logs done!

　　

vi /etc/crontab
HELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/
# run-parts
30 * * * * root /bin/clear_log.sh