Path: csiph.com!goblin3!goblin1!goblin.stu.neva.ru!usenet.stanford.edu!not-for-mail From: Peng Yu Newsgroups: gnu.bash.bug Subject: Re: Should [[ -v 1 ]] be supported? Date: Thu, 27 Dec 2018 23:32:52 -0600 Lines: 23 Approved: bug-bash@gnu.org Message-ID: References: <5dac2cf2-2fac-0fd1-058f-6a84a3271738@case.edu> <20181228013623.mersdxbzy64dpldp@crack.deadbeast.net> <20181228015710.tzzbejk36fsgr5wb@crack.deadbeast.net> NNTP-Posting-Host: lists.gnu.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-Trace: usenet.stanford.edu 1545975917 20869 208.118.235.17 (28 Dec 2018 05:45:17 GMT) X-Complaints-To: action@cs.stanford.edu Cc: bug-bash To: "G. Branden Robinson" Envelope-to: bug-bash@gnu.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wAPXBjQkOKLvhXLDyKghXScoF5Hgf+AK6C1MLd6goKA=; b=MFiTE+vruCggXYL/1fGBWurBPizBGt+aG+sb0UtfUiSaUM7NDFe4mPKTTugUB8/rFb XcoF9Gq1dDp0NgFnW0DIWmhwnMa7XnfHaOcAfKnX+EiK7RqeJurQjh9GdPZXIbRqlYs9 yWERO8mMy513NrUcaqcuaUz7ZQJj+Ip8u8Ntz9JCIAdwRwe18ZNhwqIBSaZqiP2AeNEu IILpSNRRQ8YBkcBVet+5eULXShntPECN5CJ8gMoHB98HoHA+jlJBU6UZrpHxr4zAjk1I QFAh7wXaKrI14eWBjXn7henA3dKneWkUvUoFMIAXRX08X3iaOYffs6LUbQxRg2HqMzjC EPUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=wAPXBjQkOKLvhXLDyKghXScoF5Hgf+AK6C1MLd6goKA=; b=sUY1tiaYbbYoUYxPKD5ezNQcyTZog3DbTVdc3WSZ5wN+pHMcQ77ivkswA6s6gORQhh iNOiX5imgBkFS1r27g3ZiqQ1gCu1Qu1CEjRiprguozl/AT/CbwitPLSCAPMz0ebOkI85 DpFSAbRJCYW1QoPjxaUc8Kmx2jMRM1SV6kE4RoYqZfyEqXelZQ6Syak2jfa7JcAuUbJ6 ujy/TyBsgAZK7TLEhx6pCajvabTajjx7CjTHHc67MLFL7jS1NIuAmdYVVd7n8SXaJRQQ YT6sdInpXCmvQ0PvKarfEYctp9xCLPo7lmI5T0Uuu04WHC1ZLx+l0GRPZO+ZuD0sTPCs 2luw== X-Gm-Message-State: AJcUukesmtj6u+11wLQMDqhMw4M1drDd5HbpOT86hCr8c6Q7t6uCmeFN KIeg0nUkDhx+o86NDXiUpge+fP+NmzbxsnCkENE= X-Google-Smtp-Source: ALg8bN5EymkvQOcRtU+5ulOQ5X3yXI3sf7QFVaP11oymCjftce1CIrY+xjNYXNheBCjo7ZlnaywATOFnzGaXBu9KFJE= X-Received: by 2002:a6b:6a0a:: with SMTP id x10mr6448231iog.87.1545975185009; Thu, 27 Dec 2018 21:33:05 -0800 (PST) In-Reply-To: <20181228015710.tzzbejk36fsgr5wb@crack.deadbeast.net> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::d2e X-BeenThere: bug-bash@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Bug reports for the GNU Bourne Again SHell List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Xref: csiph.com gnu.bash.bug:14986 > You're whacking moles. Use a profiler. That's what they're for. I've already shown that $() is a major problem to slow down the speed and I have reduced using its usage in my code and significantly improved the performance. Nevertheless, it doesn't mean that it is not necessary to systematically evaluating features that are used frequently. > Yes, I can. You need to identify where bash is _actually_ spending most > of its execution time, and a profiler can help you do that. Yes and no. For a particular bash script, you can quantify which bash features are the most time-consuming. But you can not profile all the bash scripts that have ever been written. Since there are only limited features in bash, in this case, a logical way to go is to at least profile each commonly used feature with minimal code (as just for and repetitive calling that features as I do) and understand its pros and cons. A profiler is an overkill in this case. -- Regards, Peng