On Fri, Sep 26, 2014 at 10:51:36AM -0400, Steve Simmons wrote: > The more I see of how many bash-isms work when bash is invoked as /bin/sh, > the more convinced I get that we need to either > > 1) make bash when invoked as /bin/sh fail those bash-isms > > 2) build a 'real' /bin/sh without those compiled in. This begs the definition > of 'real', but IMHO if it's not in POSIX, it shouldn't be in 'real' /bin/sh
Many operating systems do ship a POSIX /bin/sh which isn't bash. Ubuntu and Debian come to mind, among the Linux distributions. There are also all of the BSDs (I don't think any of them install bash as /bin/sh) and all of the commercial Unix flavors (same). The problem is, many *other* Linux distributions (even including older versions of Debian and Ubuntu) ship bash as /bin/sh, and users who are not adept at shell programming don't understand the difference. So there are untold numbers of scripts on Linux systems in the real world which use #!/bin/sh as their header, but which use some bash syntax. These will all break if the user installs dash/pdksh as /bin/sh.
