I would like to change a file so that column N+1 would be put at the end of column N for each N = odd number.
For instance, if I had a file with 4 columns, the column 2 would be pasted at the end of column 1 and the column 4 at the end of column 3.

Example file:
`
1 2 3 4
1 2 3 4
1 2 3 4`

Output file:
`
1 3
1 3
1 3
2 4
2 4
2 4`

My file have ~100 lines and ~60000 columns...

Thanks!

Mu