cat
while read -r l; do echo "$l"; done <

cat -e
while read -r l; do echo "$l"$; done <

cat -n
n=0; while read -r l; do n="$((n+1))"; printf '%5d %s\n' "$n" "$l"; done <

cat -b
n=0; while read -r l; do [ -n "$l" ] && n="$((n+1))" && printf '%5d %s' "$n" "$l"; echo; done <