In terms of pseudo-code, your task sounds sort of like this: 
declare a "master" array that will hold a set of arrays
declare a max_array_size variable, initially set to zero

for each input file {
  read its lines into a new array
  if the size of this array (# of lines in file)  > max_array_size {
    update max_array_size to this new value (size of current array)
  }
  push a reference to this array onto the "master" array.
}

for each index ( 0 .. max_array_size -1 ) {
   join the values at master[0..$#master][index] into a comma-delimite
+d string
   # note that some of the values in that set may be undef
   print the resulting string
}

[download]
HTH.

In reply to Re: arrange output in columns by graff
in thread arrange output in columns by james4545

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