'Safe printing' format is ambiguous and undocumented, and it should not be used on NUL-delimited output #130

When printing filenames (and possibly other things), lsof replaces some characters with an escaped form. However, this format is ambiguous:

> touch $'a\x0b'
> touch 'a^K'
> # Open these files, e.g. with less in two other terminals:  less $'a\x0b'  +  less 'a^K'
> lsof -Fn $'a\x0b' 'a^K'
p534276
f4
na^K
p534277
f4
na^K

Even when using the NUL-delimited output – which can safely include any possible character in a filename, since NUL bytes are not allowed there – the escaping still takes place:

> lsof -F0n $'a\x0b' 'a^K' | xxd
00000000: 7035 3334 3237 3600 0a66 3400 6e61 5e4b  p534276..f4.na^K
00000010: 000a 7035 3334 3237 3700 0a66 3400 6e61  ..p534277..f4.na
00000020: 5e4b 000a                                ^K..

There are three issues here, in my opinion:

1. The format is ambiguous on ^ escapes.
2. The format is undocumented.
3. The format should not be used on NUL-delimited output for programs because it significantly and needlessly complicates the downstream parsing.