UNIX for Dummies Questions & Answers

I have a data set that has 4 columns, I want to know if I can delete duplicate lines while ignoring one of the columns, for example

Code:

10 chr1 ASF 30
15 chr1 ASF 20
5 chr1 ASF 30
6 chr2 EBC 15
4 chr2 EBC 30
...

I want to know if I can delete duplicate lines while ignoring column 1, so the results will look like (I will of course sort, etc before I use uniq)

Code:

10 chr1 ASF 30
15 chr1 ASF 20
6 chr2 EBC 15
4 chr2 EBC 30
...

the 3rd line deleted since the information in column 2, 3, 4 has a duplicate somewhere else in the file.

I know that there's a command with uniq that lets you ignore the first n characters, but I don't have a set n, so I cannot use that. Thanks.

A long shot...

Code:

awk '!A[substr($0, index($0, " "))]++' file1 
10 chr1 ASF 30
15 chr1 ASF 20
6 chr2 EBC 15
4 chr2 EBC 30

Or

Code:

awk '!A[$2,$3,$4]++' infile

Code:

sort -t" " -k2 -k3 -k4 -u file

I think that could be reduced to:

Code:

sort -uk2 infile

Which would also sort in the 2nd, 3rd and 4th key.
Thanks Anbu, I always suspected the -u option might be in relation to the sort keys only as opposed to the whole line.
I wonder if all sort implementations work this way though.

thanks everyone!