- Your shell script is echoing information to standard output periodically in some loop
- You are just calling a program such as vmstat directly that outputs information periodically
Adding a timestamp in the two scenarios can be handled easily as follows:
Monitoring Loop
If your monitoring script includes a loop that is outputting stats periodically, a timestamp can be added to each line by capturing the output of the "date" command and then adding that information to the output line.
The output of the date command can be captured by using forward single quotes, as follows:
savedDate = `date`
Here is an example of a script making use of this technique:
#
# output stats every $1 seconds until stopped
#
if [ "$1" == "" ] ; then
echo "syntax= .stats.sh <intervalSeconds>"
exit
fi
time=$1
echo "Time , QueriesPerSechod" > mysql-stats.log
while :
do
qps=`mysql -u mysql -e "show status" | awk '{if ($1 == "Queries") print $2}'`
date=`date`
echo "$date , $qps" >> mysql-stats.log
sleep $time
done
Here is an example of the output:
Time , QueriesPerSecond
Wed Aug 8 16:11:58 PDT 2012 , 3029
Wed Aug 8 16:12:08 PDT 2012 , 18195
Wed Aug 8 16:12:18 PDT 2012 , 18903
...
Direct Output
If you are just calling an app or script such as vmstat, iostat, etc., that outputs stats periodically for you, you can achieve the same effect by piping the command through an app that prepends a timestamp to each line. For example, to prepend timestamps to the output from vmstat, free, and iostat, you would do the following, depending on a script "timestamp.sh" with the timestamp prepend behavior:
# free
free -g -s 10 | ./timestamp.sh > free.log &
# vmstat
vmstat 10 | ./timestamp.sh > vmstat.log &
# iostat
iostat 10 | ./timestamp.sh > iostat.log &
This would give output such as the following:
07/23/12 10:41:44,procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
07/23/12 10:41:44, r b swpd free buff cache si so bi bo in cs us sy id wa st
07/23/12 10:41:44, 6 0 2736 3381052 505844 159601296 0 0 62 119 1 1 6 1 93 0 0
07/23/12 10:41:54, 2 0 2736 3358836 505900 159601728 0 0 102 25 640 414 1 0 99 0 0
07/23/12 10:42:04, 7 0 2736 3329736 505948 159601936 0 0 9 32 927 1263 1 0 98 0 0
The timestamp.sh script is as follows:
#!/usr/bin/perl
#while (<>) { print localtime() . ": $_"; }
while (<>)
{
($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time);
$secpad = sprintf( "%02d", $sec );
$minpad = sprintf( "%02d", $min );
$hourpad = sprintf( "%02d", $hour );
$monpad = sprintf( "%02d", $mon );
$mdaypad = sprintf( "%02d", $mday );
$yearpad = sprintf( "%02d", ($year + 1900) % 100 );
$time = "$monpad\/$mdaypad\/$yearpad $hourpad:$minpad:$secpad";
print $time . ",$_" ;
#17/04/112 16:40:14
}
