Machine data not displaying output every 15 Seconds

Question

The following script is meant to output "vmstat" for example every 15 seconds, but for some reason it only does this if there's activity or when I kill the script, in other cases it just sits there.

#!/bin/bash
#!/bin/sh


ps -ef | grep -v grep | grep "vmstat 15" | awk '{ print $2 }' | xargs kill

ps -ef | grep -v grep | grep "iostat 15" | awk '{ print $2 }' | xargs kill

ps -ef | grep -v grep | grep "mpstat 15" | awk '{ print $2 }' | xargs kill

today=`date +%Y-%m-%d.%H:%M:%S`

find /var/log/ -name data_collection -type d -exec mv /var/log/data_collection /home/Beer/"data_collection_${today}" \;

mkdir -p /var/log/data_collection

vmstat 15 | /home/Beer/./addtimestamp.pl > /var/log/data_collection/vm_stat &
iostat 15 | /home/Beer/./addtimestamp.pl > /var/log/data_collection/ios_stat &
mpstat 15 | /home/Beer/./addtimestamp.pl > /var/log/data_collection/mp_stat &

Im guessing the '&' symbol at the end has something to do with this, I only did this so I can execute each command at once.

Answer 1

Since feature requests to mark a comment as an answer remain declined, I copy the above solution here.

What is in addtimestamp.pl? It could be that it's buffering input, and not flushing every time it reads something. – Diego Basch

@DiegoBasch that's exactly correct, I just added a '$|=1;' to the Perl script now and it started to work, basically setting the it to line buffer. Ill add the answer. – I AM L