An efficient way to transpose a file in Bash

Question

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 t

Answer 1

Another bash variant

$ cat file 
XXXX    col1    col2    col3
row1    0       1       2
row2    3       4       5
row3    6       7       8
row4    9       10      11

Script

#!/bin/bash

I=0
while read line; do
    i=0
    for item in $line; { printf -v A$I[$i] $item; ((i++)); }
    ((I++))
done < file
indexes=$(seq 0 $i)

for i in $indexes; {
    J=0
    while ((J

Output

$ ./test 
XXXX    row1    row2    row3    row4    
col1    0       3       6       9   
col2    1       4       7       10  
col3    2       5       8       11