This awk works if you have a space in front of some of the line or not cvb vs cvb @durden_tylor, you have removed this space in f02 perl gives an extra blank row due to this space
The OP did not specify an operating system, so I'll mention that because of \n in the replacement text, that sed script will fail on most non-Linux systems.
Regards,
Alister
---------- Post updated at 01:17 PM ---------- Previous update was at 01:09 PM ----------
If we assume that the sample data and sample output in the OP are exactly correct, then your solution is incorrect. The sample output has a leading space which your solution discards. Additionally, your solution adds a concluding blank line which does not appear in the sample output.
The OP should clarify exactly what they want because there is a discrepancy between the problem description and the sample input/output. The post's text appears to state (due to the grammar, it's impossible to be certain) that input fields are delimited by a single space (supported by the sample data). If that's correct, then, in the absence of special consideration (which isn't mentioned in the post) a leading space represents an empty first field which should become a blank line. However, this would cause an ambiguity in the output format, since a blank line could represent an empty field or a record separator.
If we assume that the leading space on every line of the input and output is an artifact of copy/pasting, a simple, portable solution which treats the input as newline delimited records of single-space delimited fields and converts it to blank-line delimited records (with the exception that the final record is not followed by a blank line) of newline delimited fields: