How to count number of unique values of a field in a tab-delimited text file?

Question

I have a text file with a large amount of data which is tab delimited. I want to have a look at the data such that I can see the unique values in a column. For example,

Red     Ball 1 Sold Blue    Bat  5 OnSale ...............  

So, its like the first column has colors, so I want to know how many different unique values are there in that column and I want to be able to do that for each column.

I need to do this in a Linux command line, so probably using some bash script, sed, awk or something.

What if I wanted a count of these unique values as well?

Update: I guess I didn't put the second part clearly enough. What I wanted to do is to have a count of "each" of these unique values not know how many unique values are there. For instance, in the first column I want to know how many Red, Blue, Green etc coloured objects are there.

Answer 1

You can make use of cut, sort and uniq commands as follows:

cat input_file | cut -f 1 | sort | uniq 

gets unique values in field 1, replacing 1 by 2 will give you unique values in field 2.

Avoiding UUOC :)

cut -f 1 input_file | sort | uniq 

EDIT:

To count the number of unique occurences you can make use of wc command in the chain as:

cut -f 1 input_file | sort | uniq | wc -l 

Answer 2

awk -F '\t' '{ a[$1]++ } END { for (n in a) print n, a[n] } ' test.csv