Used by awk to split the input into multiple records. For example:
echo "a b c|d e f" | awk 'BEGIN {RS="|"} {print $0}'
produces:
a b c
d e f
By default, the record separator is the newline character.
Similarly: echo "a b c|d e f" | awk 'BEGIN {RS="|"} {print $2}'
produces:
b
e