How can I add the current date or time to end of each line in file?
awk -v v1=$var ' { printf("%s,%sn", $0, v1) } ' data.txt > data.txt

sed "s/$/,$var/" data.txt

cat filename | sed "s/$/ `date`/"

awk -v v1=$var ' { printf("%s,%sn", $0, v1) } ' data.txt > data.txt

sed -i "s/$/ $var/" data.txt

awk -v "date=$var" '{print $0, date}' data.txt > tmpfile && mv tmpfile data.txt