Bash oneliners

grep -rl oldtext . | xargs sed -i 's/oldtext/newtext/g'

find /home/www \( -type d -name .git -prune \) -o -type f -print0 | xargs -0 sed -i 's/subdomainA\.example\.com/subdomainB.example.com/g'

for ip in $(cat ips.txt | awk '{print $
2}'); do if ping -c 1 -w 2 "$ip" &>/dev/null ; then echo "$ip up"; fi; done