in reply to Merging two files and changing format

C:\test>head -3 1.dat
01 01 01 01 01 01
02 02 02 02 02 02
03 03 03 03 03 03

C:\test>head -3 2.dat
A A A
B B B
C C C

C:\test>perl -nle"printf "%s",join qq[\t],split(' ',$_),do{(my$t=<STDI
+N>)=~tr/ //d;split'',$t};" <1.dat 2.dat
A       A       A       0       1       0       1       0       1     
+  0       1       0       1   0   1
B       B       B       0       2       0       2       0       2     
+  0       2       0       2   0   2
C       C       C       0       3       0       3       0       3     
+  0       3       0       3   0   3
D       D       D       0       4       0       4       0       4     
+  0       4       0       4   0   4
...

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