Shell Programming and Scripting

filename : mohan.moh.ccyymmdd.ccyymmdd.hhmmss.txt
 mohan_moh.20151222.20151222.122442.txt

IFS="." read X X D1 D2 T E < $(ls mo*.txt)
[ 8 -eq ${#D1} ] && [ 12 -ge ${D1:4:2} ] && [ 31 -ge ${D1:6:2} ]  && [ $D1 -gt 0 ] && echo OK || echo NOK

echo '20170001
20319900
20110232
20000001
20160230
20160229' |  while read d; do
  date -d$d '+%Y%m%d'; done
date: invalid date ‘20170001’
date: invalid date ‘20319900’
date: invalid date ‘20110232’
date: invalid date ‘20000001’
date: invalid date ‘20160230’
20160229

egrep '20[01][0-6](0[1-9]|1[0-2])(0[1-9]|[12][0-9]|3[01])'

awk -F '.' '{
IF($1== mohan_moh)
 then print ok 
elif ($2= --some regular expression to validate date) here $2 is 20151222
then print ok 
elif ($3= --some regular expression to validate date) here $3 is 20151222
then print ok
elif ($4= --some regular expression to validate time) here $4 is 122442
then print ok
else
 print nok
fi}