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

This might work for you (GNU sed):

sed -i 's/^\([^\t]*\t\)\([^\t]*\t\)/\2\1/' file