pdbcoluniq - find all unique values of a key column

pdbcoluniq can find all unique values of a key column, optionally including counting the number of each value seen. This is done with an internal dictionary and requires no sorting (unlike its perl dbrowuniq equivelent) at the potential cost of higher memory usage.

Example input (myfile.fsdb):

#fsdb -F s col1:l two:a andthree:d
1	key1	42.0
2	key2	123.0
3	key1    90.2

Example command usage

$ pdbcoluniq -k two -c myfile.fsdb

Example output

#fsdb -F t two count:l
key1	2
key2	1
#   | pdbcoluniq -k two -c myfile.fsdb