Shell Programming and Scripting

cat -n infile | sed 's/\t/,/g;s/\s//gw infile'

cat -n infile | sed 's/\t/,/g;s/\s//g' >infile

sed '
  #
 ' file_in |sed '
  N
  s/\n/,/
 ' > file_out

$ autotab --help

Usage: autotab [ -is <i_sep> ] [ -os <o_sep> ] [ -gh ] [ -no ] [ -j <just> ]

Scans input as columns defined by <i_sep> (default tab), measuring maximum
column width without blank padding and saving the input.  Lines with no
<i_sep> are not measured.  If -no is present (narrow, overlapping), the
characters between the last <i_sep> on a line and the line feed are not
measured.  (The -no option is only useful with left justification.)
After reading EOF, the saved input is printed, padded to the measured
column width and separated by the <o_sep> string (default 2 spaces) with
empty right side columns, blanks and carriage returns suppressed.
If -j is present, the characters of <just> define the justification of each
column with the same relative offset:
 r for right, c for centered, and anything else means left.
If -gh is present, the saved input is prefixed by a numbered column header,
which is padded and aligned like the data.
The size limits are: 4096 measured columns, output line 65536 characters
and right or center justified column data width 4096 characters.

$