If you're trying to match blob.mkv, try:
grep -Ei '^[a-z]+\.[a-z]{3}$' pow.txt
does grep regex work differently on mac?
If you're trying to match blob.mkv, try:
grep -Ei '^[a-z]+\.[a-z]{3}$' pow.txt
If you're trying to match blob.mkv, try:
grep -Ei '^[a-z]+\.[a-z]{3}$' pow.txt