bash only email if occurrence since last alert

Question

I\'m monitoring a log file for a specific word and using tac to output the 5 lines before and after it

#!/bin/bash
tac /var/log/syslog |grep -m1 -A5 -B5 \'WORD\'         


        

Answer 1

You should only search trough last 5 min of data:

data5m=$(awk '$0>=from' from="$(date +"%b %e %H:%M:%S" -d -5min)" /var/log/syslog)

Then you can grep from this data:

grep -m1 -C5 'WORD' <<< "$data5m"

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Update:

awk '$0>=from' from="$(date +"%b %e %H:%M:%S" -d -5min)" /var/log/syslog | grep -m1 -C5 'WORD'

Or all in one awk

awk '{a[NR]=$0} /pattern/ && $0>=from {f=NR} END {for (i=f-5;i<=f+5;i++) print a[i]}' from="$(date +"%b %e %H:%M:%S" -d -5min)" /var/log/syslog