Re: printf-like output for gnunet-search

Hi Alessio,

Thank you for the feedback.

I think the help text when using `--help' is too long. That's not really the place to write the _full_ explanation of the option; that's the man page's job.

Instinctively I would say that the help page grew because I was not updating the man page while I was adding features to the program, and if I did not document them immediately somewhere I would forget what I added, so I documented them in the help page. But now that there is an updated man page we can re-think the help page a bit.

This is the current output (I already started to strike things out):

$ gnunet-search --help

gnunet-search [OPTIONS] KEYWORD1 KEYWORD2 ...
Search for files that have been published on GNUnet

Keywords should start with a plus sign to indicate that they are required -
e.g. `gnunet-search commons gpl` searches for files that match *either*
"commons" or "gpl", whereas `gnunet-search +commons +gpl` searches for files
that match *both* "commons" and "gpl".

Arguments mandatory for long options are also mandatory for short options.
  -a, --anonymity=LEVEL      set the desired LEVEL of receiver-anonymity
                               (default: 1)
  -b, --bookmark-only        do not search, print only the URI that points to
                               this search
  -c, --config=FILENAME      use configuration file FILENAME
  -F, --dir-printf=FORMAT    write search results for directories according to
                               FORMAT; the format specifiers supported here
                               are identical to those supported in the
                               --printf argument (please refer to it for more
                               information); if missing, --dir-printf defaults
                               to --printf; if --printf is missing too
                               --dir-printf defaults to `#%n:\ngnunet-download
                               -o "%f" -R %u\n\n`
  -f, --printf=FORMAT        write search results according to FORMAT, where
                               %a is the complete list of all the printable
                               metadata available (each member will be
                               displayed according to the --iter-printf
                               argument) - use %j for printing only one field
                               - %f is the file's name, %l is the file name's
                               length, %m is the file's mime type, %n is the
                               search result number, %s is the file's size in
                               bytes and %u is the file's URI; the %a and %j
                               specifiers optionally support metatype
                               filtering via hash sign (e.g. `%5#j` prints a
                               book title, if present - see libextractor's
                               metatypes for the complete list of numerical
                               identifiers); if missing, --printf defaults to
                               `#%n:\ngnunet-download -o "%f" %u\n\n`
  -h, --help                 print this help
  -i, --iter-printf=FORMAT   when the %a or %j format specifiers appear in
                               --printf or --dir-printf, list each metadata
                               property according to FORMAT, where %p is the
                               property's content, %l is the content's length
                               in bytes, %t is the property type, %i is the
                               property type's unique identifier, %n is the
                               property number and %w is the name of the
                               plugin that provided the information; if
                               missing, --iter-printf defaults to `  %t: %p\n`
  -L, --log=LOGLEVEL         configure logging to use LOGLEVEL
  -l, --logfile=FILENAME     configure logging to write logs to FILENAME
  -N, --results=VALUE        automatically terminate search after VALUE
                               results are found
  -n, --no-network           only search the local peer (no P2P network
                               search)
  -o, --output=FILENAME      create a GNUnet directory with search results at
                               FILENAME (e.g. `gnunet-search
                               --output=commons.gnd commons`)
  -s, --silent               silent mode (requires the --output argument)
  -t, --timeout=DELAY        automatically terminate search after DELAY; the
                               value given must be a number followed by a
                               space and a time unit, for example "500 ms";
                               without a unit it defaults to microseconds -
                               1000000 = 1 second; if 0 or omitted it means to
                               wait for CTRL-C
  -V, --verbose              be verbose (append "%a\n" to the default --printf
                               and --dir-printf arguments - ignored when these
                               are provided by the user)
  -v, --version              print the version number

Report bugs to gnunet-developers@gnu.org.
Home page: http://www.gnu.org/s/gnunet/
General help using GNU software: http://www.gnu.org/gethelp/

Point by point…

Even the tool's description should be reverted to the simpler one-liner that was used previously.

The main reason is that it's so long to be basically unreadable.

Okay, I can do that (I already striked out the addition in the tool's description).

As an example, the help string for `--printf', which other than being about four sentences long also contains a list of items, should probably be reworded like so:

"Write search results according to FORMAT. See the documentation for the available placeholders."

Then you can add a dedicated section in the man page titled "Formatting the output" or something like that.

Here I am not sure if a description of the format specifiers can be completely absent in the help page. Man pages are not always installed by people, and a help page should be able to explain the bare minimum.

What do other people think about removing all mentions of the % format specifiers from the help page?

`--dir-printf' should use the same string, instead of referencing some other option. It is generally a good idea to treat each help message as an independent entity — at least personally speaking, oftentimes I find myself scanning the left column for a specific optiong and only after I find it I read the help text, so having to navigate back and forth because the option I need just says "alias for foo" ends up being rather annoying in the long run.

If we do mention the format specifiers in the help page, then the text of --dir-printf does become too long, and the best is that it refers to --printf like it does now. But if we remove the format specifiers from the help page, then yes, it can be its own text. However, since when not specified --dir-printf defaults to --printf, a mention of --printf will always be there in a way or another.

Maybe we can amend the output of gnunet-search --help that I pasted above directly on this mail thread?

I haven't checked the actual man pages yet, so I can't comment on that.

Below is the current output of man gnunet-search (we should also update the date at the bottom, currently “February 25, 2012”)

--madmurphy

GNUNET-SEARCH(1) BSD General Commands Manual GNUNET-SEARCH(1)

NAME

gnunet-search — a command line interface to search for content on GNUnet

SYNOPSIS

gnunet-search [−a LEVEL | −-anonymity=LEVEL] [−b | −-bookmark-only] [−c FILENAME | −-config=FILENAME] [−F FORMAT | −-dir-printf=FORMAT] [−f FORMAT | −-printf=FORMAT] [−h | −-help] [−i FORMAT | −-iter-printf=FORMAT] [−L LOGLEVEL | −-loglevel=LOGLEVEL] [−l FILENAME | −-logfile=FILENAME] [−o FILENAME | −-output=FILENAME] [−n | −-no-network] [−N VALUE | −-results=VALUE] [−s | −-silent] [−t DELAY | −-timeout=DELAY] [−v | −-version] [−V | −-verbose] ⟨ KEYWORD ⟩ ⟨ +KEYWORD ⟩ | ⟨ URI ⟩ ⟨ +URI ⟩

DESCRIPTION

Search for content on GNUnet. The keywords are case-sensitive. gnunet-search can be used both for a search in the global namespace as well as for searching a private subspace. The options are as follows:

−a LEVEL | −-anonymity=LEVEL

This option can be used to specify additional anonymity constraints. The default is 1. If set to 0, GNUnet will publish the file non-anonymously and in fact sign the advertisement for the file using your peer’s private key. This will allow other users to download the file as fast as possible, including using non-anonymous methods (discovery via DHT and CADET transfer). If you set it to 1 (default), you use the standard anonymous routing algorithm (which does not explicitly leak your identity). However, a powerful adversary may still be able to perform traffic analysis (statistics) to over time discovery your identity. You can gain better privacy by specifying a higher level of anonymity (using values above 1). This tells FS that it must hide your own requests in equivalent-looking cover traffic. This should confound an adversaries traffic analysis, increasing the time and effort it would take to discover your identity. However, it also can significantly reduce performance, as your requests will be delayed until sufficient cover traffic is available. The specific numeric value (for anonymity levels above 1) is simple: Given an anonymity level L (above 1), each request FS makes on your behalf must be hidden in L-1 equivalent requests of cover traffic (traffic your peer routes for others) in the same time-period. The time-period is twice the average delay by which GNUnet artificially delays traffic. Note that regardless of the anonymity level you choose, peers that cache content in the network always use anonymity level 1.

−b | −-bookmark-only

Do not search, print only the URI that points to the search with the given keywords.

−c FILENAME | −-config=FILENAME

Use the configuration file FILENAME (default: ~/.config/gnunet.conf).

−F FORMAT | −-dir-printf=FORMAT

Write the search results for directories according to FORMAT. The directives supported here are identical to those supported in the −-printf argument (please refer to it for more information). If missing, −-dir-printf defaults to −-printf. If −-printf is missing too −-dir-printf defaults to ‘#%n:\ngnunet-download -o %f -R %u\n\n’.

−f FORMAT | −-printf=FORMAT

Write the search results according to FORMAT, in which ‘\’ and ‘%’ directives are interpreted as follows:

a literal backslash (‘\’)

an alarm bell

a backspace

an escape

a form feed

a newline

a carriage return

a horizontal tab

a vertical tab

an ASCII NUL.

\N...

the character whose ASCII code is N..., expressed in octal digits

\xX...

the character whose ASCII code is X..., expressed in hexadecimal digits

Note: The ‘\’ character followed by any other character not listed above is treated as an ordinary character, so both characters are printed.

a percent sign

the complete list of all the printable metadata properties available, displayed according to the −-iter-printf argument; this specifier optionally supports metatype filtering via hash sign (e.g. ‘%2#a’ prints all embedded file names, if present - see libextractor’s metatypes for the complete list of numerical identifiers)

the file’s name

the first printable metadata property available, displayed according to the −-iter-printf argument; this specifier optionally supports metatype filtering via hash sign (e.g. ‘%5#j’ prints a book title, if present); see libextractor’s metatypes for the complete list of numerical identifiers)

the file name’s length

the file’s mime type

the search result number

the file’s size in bytes

the file’s URI

Note: The ‘%’ character followed by any other character not listed above is treated as an ordinary character, so both characters are printed.

If missing, −-printf defaults to ‘#%n:\ngnunet-download -o %f %u\n\n’.

−h | −-help

Print the help page.

−i FORMAT | −-iter-printf=FORMAT

When the ‘%a’ or ‘%j’ format specifiers appear in −-printf or −-dir-printf, list each metadata property according to FORMAT, in which the ‘\’ directives are interpreted as in −-printf and −-dir-printf, while the ‘%’ directives are interpreted as follows:

a percent sign

the property’s content

the property content’s length in bytes

the property type’s unique identifier

the property number

the property type (available only if compiled with libextractor)

the name of the plugin that provided the information

Note: The ‘%’ character followed by any other character not listed above is treated as an ordinary character, so both characters are printed.

If missing, −-iter-printf defaults to ‘ %t: %p\n’ or ‘ MetaType #%i: %p\n’, depending on whether the program was compiled with libextractor or not.

−L LOGLEVEL | −-loglevel=LOGLEVEL

Change the loglevel. Possible values for LOGLEVEL are ERROR, WARNING, INFO and DEBUG.

−l FILENAME | −-logfile=FILENAME

Write logs to FILENAME.

−o FILENAME | −-output=FILENAME

Writes a GNUnet directory containing all of the search results to FILENAME (e.g. ‘gnunet-search --output=commons.gnd commons’).

−n | −-no-network

Only search locally, do not forward requests to other peers.

−N VALUE | −-results=VALUE

Automatically terminate the search after receiving VALUE results.

−s | −-silent

Enable silent mode and do not print any result (the −-output argument is required).

−t DELAY | −-timeout=DELAY

Automatically timeout search after DELAY. The value given must be a number followed by a space and a time unit, for example "500 ms". Note that the quotes are required on the shell. Without a unit it defaults to microseconds (1000000 = 1 second). If 0 or omitted the search runs until gnunet-search is aborted with CTRL-C.

−v | −-version

print the version number

−V | −-verbose

append ‘%a\n’ to the default −-printf and −-dir-printf arguments – ignored when these are provided by the user

It is possible to run gnunet-search with an URI instead of a keyword. The URI can have the format for a namespace search or for a keyword search. For a namespace search, the format is

gnunet://fs/sks/NAMESPACE/IDENTIFIER

For a keyword search, use

gnunet://fs/ksk/KEYWORD[+KEYWORD]*

If the format does not correspond to a GNUnet URI, GNUnet will automatically assume that keywords are supplied directly.

If multiple keywords are passed, gnunet-search will look for content matching any of the keywords. The ‘+’ prefix makes a keyword mandatory.

FILES

~/.config/gnunet.conf GNUnet configuration file; specifies the default value for the timeout

EXAMPLES

Example 1:

$ gnunet-search ’Das Kapital’

searches for content matching the keyword “Das Kapital”

Example 2:

$ gnunet-search Das Kapital

searches for content matching either keyword “Das” or keyword “Kapital”

Example 3:

$ gnunet-search +Das +Kapital

searches for content matching both mandatory keywords “Das” and “Kapital”

Search results are printed by gnunet-search like this:

gnunet-download -o "COPYING" gnunet://fs/chk/HASH1.HASH2.SIZE

Description: The GNU General Public License
Mime-type: text/plain
...

The first line contains the command to run to download the file. The suggested filename in the example is ‘COPYING’. The GNUnet URI consists of the key and query hash of the file and finally the size of the file. If the −-verbose option was provided, after the command to download the file, GNUnet will print metadata about the file as advertised in the search result. The metadata here is the description (“The GNU General Public License”) and the mime-type (“text-plain”). See the options for gnunet-publish(1) on how to supply metadata by hand.

SEE ALSO

gnunet-download(1), gnunet-fs-gtk(1), gnunet-publish(1), gnunet.conf(5)

The full documentation for GNUnet is maintained as a Texinfo manual. If the info(1) and gnunet packages are properly installed at your site, the command

info gnunet

should give you access to the complete handbook,

info gnunet-c-tutorial

will give you access to a tutorial for developers.

Depending on your installation, this information is also available in gnunet(7) and gnunet-c-tutorial(7).

BUGS

Report bugs by using https://bugs.gnunet.org or by sending electronic mail to ⟨ gnunet-developers@gnu.org⟩ .

BSD February 25, 2012 BSD

From:	madmurphy
Subject:	Re: printf-like output for gnunet-search
Date:	Fri, 11 Feb 2022 21:05:10 +0000