Manual pages uses the quotation : `' (quoting string inside grave accent and apostrophe)

Question

I've found that many manpages uses the quotation :  `c/s'
i.e quoting character or sting inside grave accent(`) & apostophe(').

Example visit manpage of bash, find etc. and you'll find the quotation under `':

Example:

OPTIONS
    The -H, -L and -P options control the treatment of symbolic links. Command-line arguments following these are taken to be names of files or directories to be examined, up to the first argument that begins with `-', or the argument `(' or `!'. That argument and any following arguments are taken to be the expression describing what is to be searched for. If no paths are given, the current directory is used. If no expression is given, the expression -print is used (but you should probably consider using -print0 instead, anyway).

    This manual page talks about `options' within the expression list. These options control the behaviour of find but are specified immediately after the last path name. The five `real' options -H, -L, -P, -D and -O must appear before the first path name, if at all. A double dash -- can also be used to signal that any remaining arguments are not options (though ensuring that all start points begin with either `./' or `/' is generally safer if you use wildcards in the list of start points).

See the quotation used for emphasized characters. ^{I've to use escape character () to avoid undesired formatting in above quoted text (visualize it by hitting edit button!)}

So, I am curious to know about the usage of this quotation used. What is the usage of such quotation or when & why such quotation is used?

Answer 1

There are many ways quotes are handled in different languages. In my native Dutch we used „abc”. While learning to write French I had to use « abc », for English ‘abc’, or US-English “abc” and for Japanese 「abc」 (when writing horizontally).

If you copy and paste the English quotes through od with echo ‘abc’ | od -c, you get:
342 200 230 a b c 342 200 231 \n.

There it even more clear that the quote at the beginning and at the end are not the same (342 200 230 vs 342 200 231), but above all that they're both outside the ASCII character set.

The ASCII output character set used normally by the man page generating software (nroff) doesn't allow you to write any of these properly. So the combination is used to make the start-end distinction.
This is a remnant of the times that your Unix/Linux terminal couldnt display Unicode characters ( a time when unzipping a Windows generated ZIP file, or listing files on a NTFS mounted partition could make a mess of your terminal ).

Nroff, and other systems capable of generating man pages like reStructuredText and DocBook), can generate Unicode (UTF-8) output, it is just not done, either for compatibility reasons with older systems, or because nobody changed the toolchain to generate these alternative output.