Here are a few ways to do it if you want to do it from the command line in Perl:

perl -pe 's/[^:]+://' data_file > output_file

perl -nle 'print /([^:]+)$/' data_file > output_file

perl -nle 'print+(split /:/)[-1]' data_file > output_file
[download]

TMTOWTDI,
--Dave