Extract from gzip , remove duplicates from csv but keep header, then gzip result

readme.txt

# Extract a csv file from a gzip but keep the original gzip     zcat file_compressed.csv.gz
# cut the two columns of the file and save it                   cut -d',' -f1,2 > file_uncompressed.csv
zcat file_compressed.csv.gz | cut -d',' -f1,2 > file_uncompressed.csv

# Since its a csv with a header keep this header                head -n1 file_uncompressed.csv
# but get the result of the file, sort it, uniq to 
# remove duplicates, +2 so we start at line 2                   tail -n +2 file_uncompressed.csv | sort  | uniq
# gzip the result and save into new file                        gzip > file_compressed_no_dups.csv.gz
(head -n1 file_uncompressed.csv && tail -n +2 file_uncompressed.csv | sort  | uniq) | gzip > file_compressed_no_dups.csv.gz