#!/bin/sh
#ident  "@(#) 1.0  convenient way to use date for file suffix and so on  20070909 John S. Urban"
# syntax of date(1) too cumbersome
if [ "$*"  = '-h' ]
then
cat <<EOF
Easily create dates using date(1). Enter a space-delimited
list of letters from the table below:

    LETTER
       y     last two digits of year (00..99)
       m     month (01..12)
       d     day of month (e.g, 01)
       H     hour (00..23)
       M     minute (00..59)
       S     second (00..60)

       Y     year
       j     day of year (001..366)
       W     week number of year, with Monday as first day of week (00..53)
       u     day of week (1..7); 1 is Monday
       s     seconds since 1970-01-01 00:00:00 UTC
       N     nanoseconds (000000000..999999999)

The default is
  $0 Y m d

Any other strings will be printed as-is.


Examples:

   mv FILE FILE.`today`
   CMD > log.`today Y m d H M S`

   today y / m / d ' ' H : M : S
   07/08/25 02:23:33

EOF
exit
fi
#for NAME in ${@:-y m d}
[ "$*" = '' ] && set Y m d
for NAME in "$@"
do
: echo "[$NAME]" 1>&2
   case "$NAME" in
      y|m|d|H|M|S) STRING=`date +"%${NAME}"`;;
      Y|j|s|N|u|W) STRING=`date +"%${NAME}"`;;
      *)STRING="$NAME";;
   esac
   printf "%s" "$STRING"
done
printf "\n"
exit