gnu apl is an often overlooked but extremely solid APL implementation that plays nice w/ unix.

slightly verbose example but heres gnu apl as a pipe-like interface. Often this would be abstracted to a library that gets included when you call it:

  printf "1,2,3,4\n5,6,7,8" | apl --eval "f←{4⎕CR ⍵}◊s←{⍺~⍨¨⍵⊂⍨1++\⍺⋸⍵}◊f ⊃{⍎⎕UCS ⍵}¨¨44 s¨10 s⊣⎕FIO[41] 0"
  ┏→━━━━━━┓
  ↓1 2 3 4┃
  ┃5 6 7 8┃
  ┗━━━━━━━┛

DESCRIPTION:

    --eval ≡ evaluate the text

    f ≡ formatting function for printing nested values

    s ≡ partition a line of text and remove the partition character

    ⎕FIO ≡ read stdin as byte stream (see FILE_IO.apl)

    ⎕UCS ≡ convert bytes to characters

    ⍎ ≡ execute an expression (convert characters to numbers)

SUMMARY:

  read stdin as a bytestream

  partition at newlines and commas

  convert to characters

  interpret characters as numbers

  disclose into a rank-2 array

  format to stdout