Shell Programming and Scripting

 
#! /bin/ksh

format=YYYYMMDD

YEAR=${format%????}
DAY=${format#??????}
MON=${format#$YEAR}
MON=${MON%$DAY}
echo $MON/$DAY/$YEAR

YEAR=${format%????}
### Delete 4 characters from the end of format's value (format remains unchanged) 
### and return that string (YYYY in this case)

DAY=${format#??????}
### Delete 6 characters from the beginning of format's value (format remains unchanged) 
### and return that string (DD in this case)

MON=${format#$YEAR}
### Delete the string corresponding to YEAR's value (YYYY) from the beginning of format's value (format remains unchanged) 
### and return that string (MMDD in this case)

MON=${MON%$DAY}
### Delete the string corresponding to DAY's value (DD) from the end of MON's value (MMDD)
### and return that string (MM in this case)

DAY=${format:6}
MON=${format:4:2}
YEAR=${format:0:4}