From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from primenet.com.au (ns1.primenet.com.au [203.24.36.2]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id 97d36f2c for ; Fri, 31 May 2019 03:36:22 +0000 (UTC) Received: (qmail 28364 invoked by alias); 31 May 2019 03:36:07 -0000 Mailing-List: contact zsh-workers-help@zsh.org; run by ezmlm Precedence: bulk X-No-Archive: yes List-Id: Zsh Workers List List-Post: List-Help: List-Unsubscribe: X-Seq: 44383 Received: (qmail 6878 invoked by uid 1010); 31 May 2019 03:36:06 -0000 X-Qmail-Scanner-Diagnostics: from mail-pg1-f179.google.com by f.primenet.com.au (envelope-from , uid 7791) with qmail-scanner-2.11 (clamdscan: 0.101.2/25461. spamassassin: 3.4.2. Clear:RC:0(209.85.215.179):SA:0(-2.0/5.0):. Processed in 4.023555 secs); 31 May 2019 03:36:06 -0000 X-Envelope-From: akkartik@gmail.com X-Qmail-Scanner-Mime-Attachments: | X-Qmail-Scanner-Zip-Files: | Received-SPF: pass (ns1.primenet.com.au: SPF record at _netblocks.google.com designates 209.85.215.179 as permitted sender) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=KXAczzQnASokF5D9UbUk46hX2XGJEWXpv173/Oh3ZQY=; b=GlGzeFUWggQYMx9g0XcK6umu8S+JGCwVUOgNZxB/EPPrj9stO0JS7O9gl5orXveM78 KOGSz6vit3SncHiFzfcUSD2h+5OExnaWqcfr0xTG3rThqNSbz0BmAHQm0A/OVLq/wneb s/vnt/quEDeF4k0upFJtu6+fbQfMiTSKxoTmoiKxXjCix/7sLDjEUp0vfu+LmhuAxf+m SEYlSaWENM35fMbSlETsqNQKygtIfr4RCKC7ZW4sVFS+rB3hACcd4hsdUHiqNUCOxdtn iJ9XOUXW6Ibvl6mHSPeXVwdt4KN+wltShjXN5jCfUWGg5wqN6gKsZ1DIuoIYGaHdUmju xpvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=KXAczzQnASokF5D9UbUk46hX2XGJEWXpv173/Oh3ZQY=; b=kO5fUsoEJ1biY7GReM3WFZsmNOL48VsqE4TK3FftaWUKmleASP/NDm6mP37mWFgBGE qDvgWBe+lq+dmPRRZEn5wkpVVcLa/NdG1p6O/vRwRS++Q7FOd6w9Qti6zMdwP1M2nQSf dK/ZdOGv2JOmdBhw3Vs23Yf+2yMxBcY091iKOuv6OMe1D95KwdxFgWOlWaGAyOvI2P04 9IewFGP5QWPQpC8HS5TZawfiBGMhfdEEmbJ60fsWrAD15yO1u/kfqyCo8N3H2PBXPDWi o2ewpfbAmBciME0NquprsIzWIea+01kCgnMOm7yqAuEsR6eoyDV3poFm+i++mfLfnGlc RVFA== X-Gm-Message-State: APjAAAUcX0xYXbxazbbscXB3KUIZBtruFlSXylGaAJ9wl2y1TOkoKfNp A4wbUC3fMonyBu1i3rey3yjreVQPMgahRFcwg68JAKDm X-Google-Smtp-Source: APXvYqxr3AK2ts97201SJTeKQNFmI9qGGToufpm+llZ2zQYqVuaD1zylcJdq+QPI2eP7q7oO3UuqpBsTgVWCPgyGA6Q= X-Received: by 2002:a63:2848:: with SMTP id o69mr6744109pgo.258.1559273729039; Thu, 30 May 2019 20:35:29 -0700 (PDT) MIME-Version: 1.0 From: Kartik Agaram Date: Thu, 30 May 2019 20:35:17 -0700 Message-ID: Subject: pipelines transmitting data even after redirecting stdout To: zsh-workers@zsh.org Content-Type: text/plain; charset="UTF-8" In the rest of this message I'm running within a zsh sub-process without any dotfiles or inherited environment variables: env -i zsh -f This command works as expected: % echo abc > /dev/null % # no output However, adding another pipestage to it is unexpected: % echo abc > /dev/null |cat abc # whoa! If I redirect stdout to a file I seem to get some `tee`-like behavior for free: % echo abc >x |cat abc % cat x abc Is this somehow expected behavior? I've tested it on the following systems and gotten identical results: 1. zsh 5.7.1 (x86_64-apple-darwin18.2.0) on Mac OS 10.14.5 2. zsh 5.4.2 on Ubuntu 18.04 (Please explicitly include my email address in responses.) Thank you, Kartik http://akkartik.name/about