Shell 193. Valid Phone Numbers ¶ Bash 1grep -e "^[0-9]\{3\}\-[0-9]\{3\}\-[0-9]\{4\}$" -e "^([0-9]\{3\}) [0-9]\{3\}\-[0-9]\{4\}$" file.txt Was this page helpful? Thanks for your feedback! Thanks for your feedback! Help us improve this page by using our feedback form.