Unix/linux: how to arithmetic in /bin/sh and grep log based on last hours event happened

 

# calculator

y0=0

y1=0

y2=0

y3=0

t0=0

t1=0

t2=0

t3=0

getdatenow=`date +%Y/%m/%d" "%H`

getdate1hago=`date --date="1 hour ago" +%Y/%m/%d" "%H`

getdate2hago=`date --date="2 hour ago" +%Y/%m/%d" "%H`

getdate3hago=`date --date="3 hour ago" +%Y/%m/%d" "%H`

# processing today loga

y0=`grep "unable to send message to peer," /logs/UL_$yesterday\_*| grep "$getdatenow" | wc -l`

y1=`grep "unable to send message to peer," /logs/UL_$yesterday\_*| grep "$getdate1hago" | wc -l`

y2=`grep "unable to send message to peer," /logs/UL_$yesterday\_*| grep "$getdate2hago" | wc -l`

y3=`grep "unable to send message to peer," /logs/UL_$yesterday\_*| grep "$getdate3hago" | wc -l`

# processing today loga

t0=`grep "unable to send message to peer," /logs/UL_$getdate\_*| grep "$getdatenow" | wc -l`

t1=`grep "unable to send message to peer," /logs/UL_$getdate\_*| grep "$getdate1hago" | wc -l`

t2=`grep "unable to send message to peer," /logs/UL_$getdate\_*| grep "$getdate2hago" | wc -l`

t3=`grep "unable to send message to peer," /logs/UL_$getdate\_*| grep "$getdate3hago" | wc -l`

NUMBER_ERROR_DETECTED=`expr "$y0 + $y1 + $y2 + $y3 + $t0 + $t1 + $t2 + $t3" | bc`

echo $NUMBER_ERROR_DETECTED