Shell Programming and Scripting

date -d "25OCT2008" "+%d/%m/%Y"

date -d "25oct2010" "+%d/%m/%Y"

date: illegal option -- d
Usage: date [-u] [+format]
       date [-u] [mmddhhmm[[cc]yy]]
       date [-a [-]sss.fff]

#!/usr/bin/bash
check="`echo $1 | cut -c3-5`"
day="`echo $1 | cut -c1-2`"
year="`echo $1 | cut -c6-9`" 
declare -a mon_
declare -a mon_d
mon_=("Jan" "Feb" "Oct" "Nov")
mon_d=("1" "2"  "10" "11") 
limit="`echo ${#mon_[@]}`"
for (( i=0; i<=${limit}; i++ ));
do
tmp="`echo ${mon_[$i]}`"
if [ "$tmp" == "$check" ];then
check_mon="`echo ${mon_d[$i]}`"
break
fi
done 
echo "$day/$check_mon/$year"

./Ddate 22Oct2019
22/10/2019

echo 25JAN2008 |awk -F "" '
BEGIN{split("JAN FEB MAR APR MAI JUN JUL AUG SEP OCT NOV DEC",A," "); while (++i in A) M[A[i]]=i}
{sub($3$4$5,"/" sprintf("%02d",M[$3$4$5]) "/")}1'

25/01/2008

echo 25OCT2008 |awk -F "" '
BEGIN{split("JAN FEB MAR APR MAI JUN JUL AUG SEP OCT NOV DEC",A," "); while (++i in A) M[A[i]]=i}
{sub($3$4$5,"/" sprintf("%02d",M[$3$4$5]) "/")}1'
25/10/2008

echo 25Jan2008 |awk -F "" '
BEGIN{split("JAN FEB MAR APR MAI JUN JUL AUG SEP OCT NOV DEC",A," "); while (++i in A) M[A[i]]=i}
{$0=toupper($0);sub($3$4$5,"/" sprintf("%02d",M[$3$4$5]) "/")}1'

25/01/2008

 echo 25OCT2008|perl -n -e 'use Time::Piece;;/(\d\d)(\w{3})(\d{4})/;$t = Time::Piece->strptime("$1 $2 $3","%d %b %Y");print $t->strftime("%d\/%m\/%Y")."\n";'