Get last 24h of logs with AWK

For a temporary log analysis task, I wanted to get the last 24h of logs from a Postfix logfile.
To achieve this I came up with the following AWK oneliner (which fails in spectacular ways around new years):


awk -F '[ :]+' 'BEGIN{m=split("Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec",d,"|"); for(o=1;o<=m;o++){months[d[o]]=sprintf("%02d",o)}} mktime(strftime("%Y")" "months[$1]" "sprintf("%02d",$2+1)" "$3" "$4" "$5) > systime()'

This is then used in a cronjob to get a pflogsumm summary of the last 24h:


 cat /var/log/mail.log | awk -F '[ :]+' 'BEGIN{m=split("Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec",d,"|"); for(o=1;o<=m;o++){months[d[o]]=sprintf("%02d",o)}} mktime(strftime("%Y")" "months[$1]" "sprintf("%02d",$2+1)" "$3" "$4" "$5) > systime()' | pflogsumm