Date: Sun, 16 Jan 2000 22:00:22 -0500 (EST) From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> To: Alfred Perlstein <bright@wintelcom.net> Cc: Jonathan Fortin <jonf@revelex.com>, freebsd-questions@FreeBSD.ORG, doc@FreeBSD.ORG Subject: Re: sh? Message-ID: <200001170300.WAA17297@khavrinen.lcs.mit.edu> In-Reply-To: <20000116171249.L508@fw.wintelcom.net> References: <Pine.BSO.4.21.0001161858240.11142-100000@revelex.com> <Pine.BSF.4.10.10001161926130.48730-100000@pawn.primelocation.net> <20000116171249.L508@fw.wintelcom.net>
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<<On Sun, 16 Jan 2000 17:12:49 -0800, Alfred Perlstein <bright@wintelcom.net> said: > I think he wants to know why we use 'sh' instead of one > of the more popular shells. OK. I've moved the thread to -questions where it would be more appropriate. Doc team: this should go in the FAQ. The simple answer is: because POSIX says that there shall be such a shell. The more complicated answer: many people need to write shell scripts which will be portable across many systems. That's why POSIX specifies the shell and utility commands in great detail. Most scripts are written in Bourne shell, and because several important programming interfaces (make(1), system(3), popen(3), and analogues in higher-level scripting languages like Perl and Tcl) are specified to use the Bourne shell to interpret commands. Because the Bourne shell is so often and widely used, it is important for it to be quick to start, be deterministic in its behavior, and have a small memory footprint. The existing implementation is our best effort at meeting as many of these requirements simultaneously as we can. In order to keep /bin/sh small, we have not provided many of the convenience features that other shells have. That's why the Ports Collection includes more featureful shells like bash, scsh, tcsh, and zsh. (You can compare for yourself the memory utilization of all these shells by looking at the `VSZ' and `RSS' columns in a `ps -u' listing.) -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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