Linux

1. Extract phone numbers from text file People write phone numbers in various different formats. plain 10 digits number: for example, 2128174484 using hyphens to separate the digits: 212-817-4484 enclosing area code with parenthesis, and insert a dash before the extensions: (212)817-4484 Write a script to search all possible telephone numbers in a set of files. You can consider using the -f option of grep family commands to read the patterns from a file. HINT : All grep options could be in a file called phone.grep All phone numbers of any format can be in phone.txt Then, Use command grep -f phone.grep phone.txt to match phone numbers SOME EXAMPLE GREP PATTERNS would be (..not necessarily correct patterns for the problem) [0-9]\{10\}$[^0-9][0-9]\{10\}[^0-9][^0-9][0-9]\{3\}\-[0-9]\{3\}\-[0-9]\{4\}$[^0-9][0-9]\{3\}\-[0-9]\{3\}\-[0-9]\{4\}[^0-9]