Runiq functions in a manner quite similar to GNU uniq, but runiq allows you to
specify keys based on regular expressions in stead of field or the first N
characters. Runiq takes most of the options that uniq does but omits the
character and field related arguments --check-chars, --skip-fields, and
--skip-chars since the same funtionality can be achieved using Perl regular
expressions.
This arguments accepts a Perl-compatible regular expression whose grouping pairs are used to define the keys for determining the uniqueness of a line. If a regular expression is not defined, the entire line is used as the comparison key.
When this argument is given, all lines that do not match the regular expression will simply be ingored.
Counting things with arbitrary descriptions:
sinister:runiq [1]$ cat animals
gigantic ferocious man-eating duck
tiny little cow
humongous cow warrior
tiny cow peasant
massive horse
1337_ha><0rz_horse_1970_01_01
sinister:runiq [2]$ runiq --regex 'cow|horse|duck' --count animals
1 gigantic ferocious man-eating duck
3 tiny cow peasant
2 1337_ha><0rz_horse_1970_01_01
Prefix lines by the number of occurrences
Only print duplicate lines
Print all duplicate lines delimit-method={none(default),prepend,separate} Delimiting is done with blank lines
ignore differences in case when comparing
Only print unique lines
End lines with 0 byte, not newline
Display help and exit
Right now, the program is not quite as useful as it could be when the input needs to be sorted. I will create an rsort to complement this script to allow sorting based on regular expressions.