Concatenate two columns of a text file

Question

I have a tsv file like

1   2   3   4   5   ...
a   b   c   d   e   ...
x   y   z   j   k   ...

How can I merge two contiguous columns, say the 2nd and the 3rd, to get

1   2-3   4   5   ...
a   b-c   d   e   ...
x   y-z   j   k   ...

I need the code to work with text files with different numbers of columns, so I can't use something like awk 'BEGIN{FS="\t"} {print $1"\t"$2"-"$3"\t"$4"\t"$5}' file

awk is the first tool I thought about for the task and one I'm trying to learn, so I'm very interested in answers using it, but any solution with any other tool would be greatly appreciated.

Answer 1

With simple sed command for tsv file:

sed 's/\t/-/2' file

The output:

1   2-3 4   5   ...
a   b-c d   e   ...
x   y-z j   k   ...

Answer 2

Following awk may help you in same, in case you are not worried about little space which will be created when 3rd field will be nullified.

awk '{$2=$2"-"$3;$3=""} 1'  Input_file