UNIX for Beginners Questions & Answers

tail < filename> | tail -100 > /tmp/log.a
tail < filename> | tail -200 > /tmp/log.b
tail < filename> | tail -500 > /tmp/log.c
cat < filename> ( full file ) > /tmp/log.e
cat < filename> | grep "sept 10 2019"> /tmp/log.f
cat <filename> | grep encrypt > /tmp/log.g

if [[ `grep "encrypt" /tmp/log.g` != "0" ]]
then
exit 0
else
mailx -s "Message Title." user@domain < /tmp/log.g
fi

FL=$(wc -l < inputfile)
while read
  do    case $REPLY in
        [tT]*)  CMD="NR>$((FL - ${REPLY:1}))";;
        [pP]*)  CMD="/${REPLY:1}/";;
        [fF]*)  CMD=1;;
            *)  echo "usage: CMD Param; CMD ~ t)ail, p)attern search, f)ull"
                continue
        esac

        ((++CNT))
        awk "$CMD" inputfile > /tmp/log.$CNT
  done