Re: bash sockets: printf \x0a does TCP fragmentation

From	dirk+bash@testssl.sh
Newsgroups	gnu.bash.bug
Subject	Re: bash sockets: printf \x0a does TCP fragmentation
Date	2018-09-22 12:49 +0200
Message-ID	<mailman.1135.1537613418.1284.bug-bash@gnu.org> (permalink)
References	<c6de6616-dda0-570d-de56-419e7676be8a@cbii-hh.de> <69b48113-bc58-e0c8-a551-03a7e72d88d4@case.edu> <1a70754f-4302-1c96-1ae3-5ab9bdbdf8c3@iki.fi>

Show all headers | View raw


On 9/22/18 12:38 PM, Ilkka Virta wrote:
> On 22.9. 02:34, Chet Ramey wrote:
>> Newline? It's probably that stdout is line-buffered and the newline causes
>> a flush, which results in a write(2).
> 
> Mostly out of curiosity, what kind of buffering logic does Bash (or the builtin
> printf in particular) use? It doesn't seem to be the usual stdio logic where you get
> line-buffering if printing to a terminal and block buffering otherwise. I get a
> distinct write per line even if the stdout of Bash itself is redirected to say
> /dev/null or a pipe:
> 
>  $ strace -etrace=write bash -c 'printf "foo\nbar\n"' > /dev/null
>  write(1, "foo\n", 4)                    = 4
>  write(1, "bar\n", 4)                    = 4
>  +++ exited with 0 +++

Oh. But thanks anyway!

coreutils in fact does it in one shot as you indicated.


Dirk

Back to gnu.bash.bug | Previous | Next | Find similar | Unroll thread

Thread

Re: bash sockets: printf \x0a does TCP fragmentation dirk+bash@testssl.sh - 2018-09-22 12:49 +0200

csiph-web