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Processed in 3.838678 secs); 06 Sep 2018 12:55:52 -0000 X-Envelope-From: p.stephenson@samsung.com X-Qmail-Scanner-Mime-Attachments: | X-Qmail-Scanner-Zip-Files: | DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20180906125545euoutp01d3dc0ebc02f93a875f2d2af78bba7a59~R0NFKrbVW1854418544euoutp01V DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1536238545; bh=zLvVF+zJ/qTbap67H3Pmgv99qJHyId3WeSOMWw679oE=; h=Date:From:To:Subject:In-Reply-To:References:From; b=bx5oIio6IUs1Pq5PgXyyMSSy2IWAmPp8iBaAD3h1oHspbwzbrw6bZgIxiAbKlSIz7 lAOq2SL4NaEMMVLu6AI1FVK1c3n71IzFfNpFWcKGxG7Uz2dKFHZMeUy2ulwykSdmkL K55gFJrEi8N6O8aDzEm6U69zHK5pSwiySAlYJw2M= X-AuditID: cbfec7f4-835ff700000010c6-b0-5b9123d01fc2 Date: Thu, 6 Sep 2018 13:55:42 +0100 From: Peter Stephenson To: Subject: Re: zsh 5.6 regression: a pipe sometimes yields a TTOU signal In-Reply-To: <20180906123657.GD29649@cventin.lip.ens-lyon.fr> Organization: SCSC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrLIsWRmVeSWpSXmKPExsWy7djPc7oXlCdGG6xaxmFxsPkhkwOjx6qD H5gCGKO4bFJSczLLUov07RK4Mnafes5csIy94vKnfywNjFdYuxg5OSQETCSWNr5i7mLk4hAS WMEo8b15MxuE08ckcWz/DbAqIYFeJomujbEwHRe7vrJAFC1nlJj4bwqUA1S05PZ/qPbTjBK/ 771nhXDOM0oc3HWCHaSfRUBF4mzPazCbTcBQYuqm2YwgtoiApMS15tNANgeHsICbxL1dlSBh TgFbiUtXtoKF+QWEJC4020JcYS9xdM9JJhCbV0BQ4uTMJywgNrOAvMT2t3PA/pEQ+MwmcXjB F1aIojKJW88+MEM0u0icOreJCcIWlnh1fAs7hC0j8X/nfCaI5nZGiTWTQO4EcXoYJTYdvcMI UWUt0Xf7IthFzAKaEut36YOYEgKOEp+/eEOYfBI33gpC3MMnMWnbdGaIMK9ER5sQxAw1iR1N WxknMCrPQvLBLCQfzEIYv4CReRWjeGppcW56arFRXmq5XnFibnFpXrpecn7uJkZgIjj97/iX HYy7/iQdYhTgYFTi4V1wrj9aiDWxrLgy9xCjBAezkgive/WEaCHelMTKqtSi/Pii0pzU4kOM 0hwsSuK8fFpp0UIC6YklqdmpqQWpRTBZJg5OqQZG2+orKrM4dvt8n3sr/0nSBc7WT3JBYf8n Tr/fMe2vz0mzh2dScyfVzp7CP3Xxj45TUnM1atfzG3Htqr613e72arFLeuqfDW/aGy0KXXVA 8sOUyAkbZgmuOfBs9dSXOse5w92uvd7RvfnYbHlfThfFR/dtdu+7098y28fJePPXt4vmz9E2 OplztFOJpTgj0VCLuag4EQDaxDXJAAMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFuphkeLIzCtJLcpLzFFi42I5/e/4Xd3zyhOjDbZeErI42PyQyYHRY9XB D0wBjFF6NkX5pSWpChn5xSW2StGGFkZ6hpYWekYmlnqGxuaxVkamSvp2NimpOZllqUX6dgl6 GbtPPWcuWMZecfnTP5YGxiusXYycHBICJhIXu76ydDFycQgJLGWUaPh5GSohI/Hpykd2CFtY 4s+1LjaIom4miUP9m8ASQgKnGSVO9vNBJM4zSvycsIUZJMEioCJxtuc1WBGbgKHE1E2zGUFs EQFJiWvNp4FsDg5hATeJe7sqQcK8As4S19/tA1vMKWArcenKVkaImadZJXa2PmEHqecXEJK4 0GwLcZC9xNE9J5kgegUlTs58wgJiMwvoSJxYdYwZwpaX2P52DvMERuFZSMpmISmbhaRsASPz KkaR1NLi3PTcYkO94sTc4tK8dL3k/NxNjMCY2Hbs5+YdjJc2Bh9iFOBgVOLhXXCuP1qINbGs uDL3EKMEB7OSCK979YRoId6UxMqq1KL8+KLSnNTiQ4ymwLCYyCwlmpwPjNe8knhDU0NzC0tD c2NzYzMLJXHe8waVUUIC6YklqdmpqQWpRTB9TBycUg2MZadFOh6cPrz0xtMfpQ1JakxLqpv+ GM1Okppfz77Vs/yWpmReTP4t06uLlih8eahbq9145+bM6d7WS0uzFZKn8r/T/Zw/e9mJDw1S a1JvrRQxZvZesTCupO337FfsWyNkDH/ppRyoERW/u6B8jUbeiU/xWtcbbs+4GnrMRj+wZ4E0 c9xSPf0IJZbijERDLeai4kQA0ci+RZ8CAAA= Message-Id: <20180906125543eucas1p1368a619a1ff04988622b864e38f9c4f6~R0NDo76GJ0949909499eucas1p13@eucas1p1.samsung.com> X-CMS-MailID: 20180906125543eucas1p1368a619a1ff04988622b864e38f9c4f6 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20180905091407epcas1p1ff78da39bfd4f3e4201f467683288a7b X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20180905091407epcas1p1ff78da39bfd4f3e4201f467683288a7b References: <20180905090339.GA18116@cventin.lip.ens-lyon.fr> <20180905100356eucas1p29702acd7569a94c8c78003e6b124daaa~ReNxz4yht0327203272eucas1p2s@eucas1p2.samsung.com> <20180905105510.GA2116@cventin.lip.ens-lyon.fr> <20180905122246.GA4516@cventin.lip.ens-lyon.fr> <20180905131706.GB4516@cventin.lip.ens-lyon.fr> <20180905133704.GC4516@cventin.lip.ens-lyon.fr> <20180905144049eucas1p29a22151c8a47745343b899adefaa3fc2~Rh-iZ0O7_1601216012eucas1p2j@eucas1p2.samsung.com> <20180906114011.GA29649@cventin.lip.ens-lyon.fr> <20180906122618.GC29649@cventin.lip.ens-lyon.fr> <20180906123657.GD29649@cventin.lip.ens-lyon.fr> On Thu, 6 Sep 2018 14:36:57 +0200 Vincent Lefevre wrote: > Perhaps I misunderstood. The solution is not something like > > echo | { ( sww ) | less } > > but > > echo | ( sww | less ) Yes, that's what I meant. In the first example there are still Rimmerworld(*) pipelines: "echo | ... " and "(sww) | less" are two different pipelines being managed in the same shell. This is the root of the problem, with various ramifications. In the second case, "echo | ..." is in one shell, and then "sww | less" is managed entirely by a forked copy of the shell, so the basic issue doesn't occur. In principle (and depending a bit on options, open FDs, etc.) the second one should be just as efficient --- the fork occurs earlier but the "less" is run by an exec of the forked shell. pws (*) https://www.youtube.com/watch?v=py3u3P9OpBE OK, the actual relevance *is* a bit obscure.