Transpose a file in bash

Posted by Thrawn on Stack Overflow See other posts from Stack Overflow or by Thrawn
Published on 2009-11-13T15:13:46Z Indexed on 2010/03/21 22:41 UTC
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Hi all,

I have a huge tab-separated file formatted like this

X column1 column2 column3
row1 0 1 2
row2 3 4 5
row3 6 7 8
row4 9 10 11

I would like to transpose it in an efficient way using only using commands (I could write a ten or so lines Perl script to do that, but it should be slower to execute than the native bash functions). So the output should look like

X row1 row2 row3 row4
column1 0 3 6 9
column2 1 4 7 10
column3 2 5 8 11

I thought of a solution like this

cols=`head -n 1 input | wc -w`
for (( i=1; i <= $cols; i++))
do cut -f $i input | tr $'\n' $'\t' | sed -e "s/\t$/\n/g" >> output
done

But it's slow and doesn't seem the most efficient solution. I've seen a solution for vi in this post, but it's still over-slow. Any thoughts/suggestions/brilliant ideas? :-)

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