mjhjmtu

I have a crontab script which monitor a DR process between 2 machines and this script generate a log file. What i have been asked to do is basically append the new log generated on the top of the previous (as log i use the same file name) and not on the bottom.

I've seen already few options, but all my tentative failed.

I tried with

cat $LOGFILE >> $TEMPLOG
rm $LOGFILE
mv -i $TEMPLOG $LOGFILE

and also with

cat - $LOGFILE > $TEMPLOG && mv $TEMPLOG $LOGFILE

the variable $LOGFILE is where the script append every single statement of the process.

Thanks :)

Basically want I'd like to to do is generate the right log with on top the last run before it is sent by mail.

DATE=`date "+%d%m%y_%H%M"`
PRIMARY_HOSTNAME=`hostname`
LOGFILE=/dba/logs/monitor_sync_FM2.log
TEMPLOG=/dba/logs/monitor_sync_LOG.log
SERVER=`hostname`
SITE=mycompany
EMAILTO="email@company.com"
DBOPS="oracle@$SERVER.$SITE"

export PRIMARY_HOSTNAME LOGFILE TEMPLOG SERVER SITE EMAILTO DBOPS DATE
echo "nn### monitor DR sync started @ `date` ###" >> $LOGFILE
echo "Running SQL command to verify latest SCN.." >> $LOGFILE
echo "The current SCN of the Primary DB server is: $PRIMARY_CURRENT_SCN" >> $LOGFILE

echo "Connecting now to the secondary standby database server..." >> $LOGFILE
SECONDARY_CURRENT_SCN=`ssh oracle@xxx.xxx.xxx.xxx /home/oracle/script_sync2.sh` >> $LOGFILE
export SECONDARY_CURRENT_SCN
echo "Secondary SCN output returned as: $SECONDARY_CURRENT_SCN" >> $LOGFILE
grep ORA- /dba/scripts/output.txt
if [ $? = 0 ]; then
echo "Remote ssh command to Secondary server failed..Exiting" >> $LOGFILE
echo "### monitor DR sync failed @ `date` ###" >> $LOGFILE
echo "PROBLEM" >> $LOGFILE

mailx -r $DBOPS -s "PROBLEM" $EMAILTO < $LOGFILE
exit
else
echo "The current SCN of the Secondary DB server is: $SECONDARY_CURRENT_SCN" >> $LOGFILE
DIFF=`expr $PRIMARY_CURRENT_SCN - $SECONDARY_CURRENT_SCN` ; export DIFF
if [ $PRIMARY_CURRENT_SCN -ne $SECONDARY_CURRENT_SCN ]; then
 echo "The difference is $DIFF" >> $LOGFILE
 if [ `echo $DIFF` -gt 3 ]; then
 echo "Log Gap: $DIFF" >> $LOGFILE
 echo "PROBLEM" >> $LOGFILE
 echo "### script finished @ `date` ###nn" >> $LOGFILE
 mailx -r $DBOPS -s "PROBLEM" $EMAILTO < $LOGFILE
 else
 echo "SUCCESS" >> $LOGFILE
 mailx -r $DBOPS -s "SUCCESS" $EMAILTO < $LOGFILE
 echo "Log Gap: $DIFF" >> $LOGFILE
 fi
else
echo "Log Gap: $DIFF" >> $LOGFILE
echo "SUCCESS" >> $LOGFILE
mailx -r $DBOPS -s "SUCCESS" $EMAILTO < $LOGFILE
fi
fi

If you want to "append" (insert) the current run's logs to the beginning of the existing log file, then follow through with your apparent attempt at using a TEMPLOG file. Write all of the script's output/data to that $TEMPLOG file, then do:

ed -s $LOGFILE <<< "0r $TEMPLOG"$'n'wq

To read $TEMPLOG into $LOGFILE after line zero.

As an example:

$ cat logfile
previous
entries
here
$ cat templog
New
Entry goes
Here
$ ed -s "$LOGFILE" <<< "0r $TEMPLOG"$'n'wq
$ cat logfile
New
Entry goes
Here
previous
entries
here

If your shell does not support here-strings, print the instructions to ed's stdin instead:

printf "0r $TEMPLOGnwqn" | ed -s logfile

If you only need the contents of the email to be changed, and not the $LOGFILE itself, just prepend it in the pipe to mail:

cat "$TEMPLOG" "$LOGFILE" | mailx -r $DBOPS -s "SUCCESS" $EMAILTO

Since your script appends to $LOGFILE, I think what you want is

mv $LOGFILE $TEMPLOG

at the beginning and

cat $TEMPLOG >>$LOGFILE

just before mailing.