awk - Find duplicate records with only text case difference -

i have log file 8m entries/records urls. i'd find duplicate urls (same urls) difference being type / text case.

example:

origin-www.example.com/this/is/hard.html origin-www.example.com/this/is/hard.html origin-www.example.com/this/is/hard.html

in case, there 3 duplicates case sensitivity.

output should count -c , new file duplicates.

use typical awk '!seen[$0]++' file trick combined tolower() or toupper() make lines in same case:

$ awk '!seen[tolower($0)]++' file origin-www.example.com/this/is/hard.html

for different output , counters whatsoever, provide valid desired output.

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