Program is coded in BASH. code.sh is the BASH file. subham is the output file. Directory test case contains 3 txt files for test purpose.
Following variation in Indian mobile numbers has been considered: 9990020287 09990020287 919990020287 0919990020287 +919990020287 +91 9990020287 +91-9990020287 +91 -9990020287 +91- 9990020287 +91 - 9990020287