Ping sweep from 10.0.1.1 to 10.0.1.31:
for i in {1..31}; do ping -c 1 10.0.1.$i | fgrep ttl & done 2>/dev/null | sed -e 's/^.*from //' -e 's/:.*$//' | sort -n -t. -k4
Result:
10.0.1.1 10.0.1.2 10.0.1.3 10.0.1.7 10.0.1.9 10.0.1.10 10.0.1.12 10.0.1.13 10.0.1.14 10.0.1.15 10.0.1.16 10.0.1.17 10.0.1.18 10.0.1.19 10.0.1.20