Question

For example… if I had a file like this:

A   16  chr11   36595888
A   0   chr1    155517200
B   16  chr1    43227072
C   0   chr20   55648508
D   0   chr2    52375454
D   16  chr2    73574214
D   0   chr3    93549403
E   16  chr3    3315671

I need to print only the lines which have a unique first column:

B   16  chr1    43227072
C   0   chr20   55648508
E   16  chr3    3315671

It’s similar to awk '!_[$1]++', but I want to remove all lines which have non-unique fist field.

Bash and python solutions preferably.

Answer 1

in bash, assuming first column has fixed with (3):

sort input-file.txt | uniq -u -w 3

‘-u’ option prints only the unique lines and ‘-w 3’ compares no more than the first 3 characters.