Stephane CHAZELAS wrote: > There's a common confusion in this in the nature of /bin/sh. > There's no standard (neither POSIX nor Unix) that specifies that > /bin/sh should be any variant of the Bourne shell.
Sure there is, POSIX. Or rather their Austin Group. And while they done an extremely poor job of it the POSIX shell is still the Bourne shell, /bin/sh as it's always been known, with a few enhancements such as tilde expansion and such. > Over the years and on the different flavours of Unix, /bin/sh > has been a Thomson shell, Mashey shell, Bourne shell and all its > variants, Almquist shell, bash, ksh, zsh... Zsh? Seriously? Where? The fact that various flavors of Linux have used various poorly designed "compatiblity mode" hacks to circumvent Bourne/POSIX regardless of compatibility consequences does not change the fact that /bin/sh is still there in all distributions, is still the cross-platform compatibility winner by a county mile, and can still be relied on for shell scripts. >should have somewhere (and the location is not specified but on >most Unices except those quoted above is generally /bin) a >command called "sh" that is an interpreter of the POSIX shell >language it defines. Right, that's /bin/sh. It's common name is the Bourne shell even though it is not the code that Mr Bourne wrote years ago, and even though GNU/POSIX and ATT/David Korn want to remake it into a "POSIX shell" regardless of the compatibility consequences. >That shell language is based on a subset of the ksh88 language >and the Bourne shell is not a conformant implementation. Only if you limit your use of the term "Bourne shell" to something that the rest of us don't recognize as a Bourne shell. The fact that POSIX has been known to jerry-rig ksh features (most of which werre derived from tcsh by the way) into /bin/sh (and sort, and a few other APIs they really should not be changing) only reflects the fact that A) David Korn (still with ATT) has been pushing his vision, and B) systems administrators (the ones who suffer most from cross-platform incompatibilities) are not well represented within POSIX in general, and not well represented within its Austin Group in particular. Tam -- http://mail.python.org/mailman/listinfo/python-list
