The man page for dd(1) describes the "sync" parameter of the "conv=" option thusly: sync Pad every input block to the input buffer size. Spaces are used for pad bytes if a block oriented conversion value is specified, otherwise NUL bytes are used. This verbage is entirely unclear. What is a "block oriented conversion value" and how would a user know whether or not he had specified one? The man page should make this more clear & explicit. Fix: I don't know what the fix is because I don't have the vaguest idea what a "block oriented conversion value" is. How-To-Repeat: man 1 dd
Well, the "conversion value" is the set of all parameters that you have supplied to "conv" - you can supply more than one using commas. And I think that "block-oriented" should mean that some of the things that you have specified say that the output should be in blocks - either that it is in blocks by default (and you have *not* requested unblocking it by using "ascii", "oldascii" or "unblock"), or that you've requested that dd(1) make it into blocks using one of the "block", "ebcdic", "ibm", "oldebcdic" and "oldibm" conversion specifiers. Of course, I could be wrong, but that's how I myself understand the manual page. G'luck, Peter -- Peter Pentchev roam@ringlet.net roam@FreeBSD.org p.penchev@storpool.com PGP key: http://people.FreeBSD.org/~roam/roam.key.asc Key fingerprint 2EE7 A7A5 17FC 124C F115 C354 651E EFB0 2527 DF13 No language can express every thought unambiguously, least of all this one.
In message <20130329131835.GA15952@straylight.m.ringlet.net>, you wrote: >Of course, I could be wrong, but that's how I myself understand the >manual page. Thank you, but I think that the important point here is that the man page should be clear about all this, so that people can use the tool without guessing as to the semantics, and without having to rely on additional sources of information about the semantics (e.g. the source code). Regards, rfg
For bugs matching the following criteria: Status: In Progress Changed: (is less than) 2014-06-01 Reset to default assignee and clear in-progress tags. Mail being skipped
The POSIX man page is informative: https://www.unix.com/man-page/posix/1posix/dd/
Created attachment 228338 [details] dd(1) patch After reading the source code, the sync option has three possible characters to pad the input block with. First is the user-specified value of fillchar; second is a space when block, noblock, ascii, ebcidic, or their synonyms are specified; and a NUL character otherwise. Document this behavior by updating dd(1).