Shell Programming and Scripting

dow= (epochseconds / 86400 ) % 7

#!/bin/sh

# Day of the week (YYYYMMDD)

d="20101007"

day=${d#??????}
temp=${d#????}
month=${temp%??}
year=${d%????}

DOW=$(cal $month $year | awk '
BEGIN{split("Sun Mon Tue Wed Thu Fri Sat",dow);dow[0]=dow[7]}
NR==3{t=7-NF+d;print dow[t%7];exit}' d=$day)

echo $DOW

# date -j -f "%Y%m%d" "20101007" "+%A"
Thursday

# date -d 20101007 "+%A"
Thursday

awk 'BEGIN{
	FS="|";
	while(getline < "DAY_MAPPING_NEW.CFG")
	{
	DAY_NEW[$2]=$1; DAY_NEW[$3]=$1; DAY_NEW[$4]=$1; DAY_NEW[$5]=$1; DAY_NEW[$6]=$1; DAY_NEW[$7]=$1;
	}
}
{
	dd=substr("'${DATE}'",7,2);
	mm=substr("'${DATE}'",5,2);
	yyyy=substr("'${DATE}'",1,4);
	system("cal "mm" "yyyy" | tail -7|tr \" \" \";\"|tr \"\\n\" \";\" >out.txt");
	while(getline < "out.txt")
	{OPFILE=$0;}
	if (int(dd) <= 9) {	dd=substr("'${DATE}'",8,1);	}
	newdd=";"dd";"
	daynum=index(OPFILE,newdd);
	print "New Date is:"dd"|"mm"|"yyyy"|"DAY_NEW[daynum];
	system("rm out.txt");


	OTHER FUNCTIONALITIES
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}' INPUTFILE.txt