Every new block.
milton@milton:~$ ps -eo cmd | egrep bitcoind | egrep -v grep
bitcoind -daemon -blocknotify=blocknotify %s
#!/bin/bash -e
block_message()
{
local DATE=$1
local HEIGHT=$2
local BLOCKHASH=$3
echo -e "+====================================================================="
echo -e "| \033[31m ${DATE} \033[0m"
echo -e "+====================================================================="
echo -e "| \033[31m ${HEIGHT} \033[0m"
echo -e "+====================================================================="
echo -e "| \033[31m ${BLOCKHASH} \033[0m"
echo -e "+====================================================================="
} >> $HOME/temp/blocknotify.txt
block_message "$(date -u)" "$(bitcoin-cli getblockcount)" "$@"
milton@milton:~$ tail -f temp/blocknotify.txt
+====================================================================+
| 0000000000000000016c397b5eac0d5b3580d11b585996d2a8452bef2e03fa3e |
+====================================================================+
+====================================================================+
| Wed Apr 20 23:49:27 UTC 2016
+====================================================================+
| 408221
+====================================================================+
| 0000000000000000033ed3a5284a10c8992cb9411bf4fd33a130fc742436e3f7 |
+====================================================================+