Swap two columns - awk, sed, python, perl

Question

I\'ve got data in a large file (280 columns wide, 7 million lines long!) and I need to swap the first two columns. I think I could do this with some kind of awk for loop, to

Answer 1

I tried the answer of perreal with cygwin on a windows system with a tab separated file. It didn't work, because the standard separator is space.

If you encounter the same problem, try this instead:

awk -F $'\t' ' { t = $1; $1 = $2; $2 = t; print; } ' OFS=$'\t' input_file

Incoming separator is defined by -F $'\t' and the seperator for output by OFS=$'\t'.

awk -F $'\t' ' { t = $1; $1 = $2; $2 = t; print; } ' OFS=$'\t' input_file > output_file