[Bug 141481] Re: dash as #!/bin/sh introduces countless incompatibilities
There is one more DASH bug. Described here: http://groups.google.com/group/vim_use/browse_thread/thread/837988813a06c280/f8b4aadd575affaa?lnk=gst&q=expect#f8b4aadd575affaa -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/141481 Title: dash as #!/bin/sh introduces countless incompatibilities To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dash/+bug/141481/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 141481] Re: dash as #!/bin/sh introduces countless incompatibilities
If GDM is sourcing the user's setup files using any shell other than the user's defined shell (from getpwent() or whatever) then that's a bug in GDM. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/141481 Title: dash as #!/bin/sh introduces countless incompatibilities -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 141481] Re: dash as #!/bin/sh introduces countless incompatibilities
At the very least, Ubuntu should make sure user's rc scripts (~/.profile, which sources ~/.bashrc for instance) does not contain dash-incompatible code by default, as it currently does. Programs like gdm source those but are run from dash resulting in user's stuff not being sourced before startup applications from ~/.config/autostart are lounched. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/141481 Title: dash as #!/bin/sh introduces countless incompatibilities -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 141481] Re: dash as #!/bin/sh introduces countless incompatibilities
Not really wanting to get into this debate, but having had my tutorial linked here and associated with an opinion, I must clarify that my ideal for UNIX and Linux systems is that /bin/sh be in some way consistent, and provide all Bourne functionality. That is, my personal view is that stating "#!/bin/sh" says that SVR4 sh is expected; scripts that assume bash should state "#!/bin/bash" (or possibly "#!/usr/bin/bash", which is a different issue). That is academic; the point of this post is to refute the statement that "http://steve-parker.org/sh/sh.shtml ... mostly cover[s] outdated incompatabilites between other shells." -- dash as #!/bin/sh introduces countless incompatibilities https://bugs.launchpad.net/bugs/141481 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 141481] Re: dash as #!/bin/sh introduces countless incompatibilities
Temporary tricks for running an sh scripts http://liquidweather.net/howto/index.php?id=59 -- dash as #!/bin/sh introduces countless incompatibilities https://bugs.launchpad.net/bugs/141481 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 141481] Re: dash as #!/bin/sh introduces countless incompatibilities
This is also being discussed on http://brainstorm.ubuntu.com/idea/2225/ - make your vote count ;-) -- dash as #!/bin/sh introduces countless incompatibilities https://bugs.launchpad.net/bugs/141481 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 141481] Re: dash as #!/bin/sh introduces countless incompatibilities
I have written https://wiki.ubuntu.com/DashAsBinSh (a new version, to replace the spec that used to be there) to address many of these issues, and linked it from the Edgy release notes. As far as non-POSIX constructs go, Paul Smith is right on the money with his comments in https://bugs.launchpad.net/ubuntu/+source/dash/+bug/141481/comments/4, I think. The proper analogy is a C compiler: it is not a bug in the C compiler if it stops accepting code that doesn't conform to the standard and doesn't declare that it uses an extension (in this case, by saying #! /bin/bash). This is of course not to say that the real dash bugs that have been identified here should not be fixed. -- dash as #!/bin/sh introduces countless incompatibilities https://bugs.launchpad.net/bugs/141481 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 141481] Re: dash as #!/bin/sh introduces countless incompatibilities
First, we have to make a distinction between the issues described here
which are POSIX and which mean that there is a bug in dash that should
be fixed, and those which are NOT POSIX, of which, contrary to the
assertion above, there are definitely some. For example:
$ dash -c 'a=water;echo ${a:2:2}'
dash: Syntax error: Bad substitution
is not POSIX: POSIX does not define substring syntax. Also:
$ dash -c 'echo $UID'
# no output. how on earth are we supposed to safely and portably get the UID?
POSIX does not define that the shell should set the UID variable. You
have to use "id".
$ dash -c 'x="1 2"; local y=$x; echo $y'
local: 1: 2: bad variable name
I don't think "local" is defined in POSIX sh, although it appears dash
does try to implement it; if so it should be done right.
$ dash -c 'cnt=6; while [ $((cnt = cnt - 1)) -gt 0 ]; do echo $cnt; done'
dash: arith: syntax error: "cnt = cnt - 1"
I don't think assignment inside arithmetic expressions is defined in
POSIX.
The rest of these do appear to be bugs in dash, although technically the
POSIX spec only guarantees the shell to handle file descriptors 0-9 so
using any FD >9 is not, strictly, portable.
My opinion is that Ubuntu is 100% correct here: they should be using
POSIX shell scripts and any script that does not adhere to POSIX should
NOT start with #!/bin/sh. Obviously where dash doesn't support POSIX
that's a bug in dash that needs to be fixed.
But, I hope Ubuntu will not bow down to this decade's version of "all
the world's a VAX" and make more true the maxim "every /bin/sh is bash".
Fight the good fight, Ubuntu!
--
dash as #!/bin/sh introduces countless incompatibilities
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[Bug 141481] Re: dash as #!/bin/sh introduces countless incompatibilities
POSIX compliance is exactly the heart of this. Just because dash *claims* to comply with the standard doesn't necessarily mean that it *actually* does. Specifically, as quoted in bug #92189, section 2.6.4 of IEEE 1003.1 states If the shell variable x contains a value that forms a valid integer constant, then the arithmetic expansions "$((x))" and "$(($x))" shall return the same value. If dash doesn't behave this way, which it doesn't, then it is not POSIX compliant. That being said, I don't believe that POSIX requires /bin/sh to be compliant. However, the whole trend in *nix systems over the last decade or two has been to _improve_ interoperability by adhering to standards. Using a non-POSIX shell for /bin/sh clearly goes against that trend. It seems pointless to introduce these compatibility issues that require either editing an enormous number of scripts or reconfiguring systems to symlink /bin/sh to bash instead of dash just to save a few kb of disk space. In my opinion, that is doubly so since the incompatibility is recently introduced. That is, /bin/sh _used_ to be bash, and it was (IMO gratuitously) changed in a way that created problems. The maintainers should acknowledge the error and either patch dash to actually comply with POSIX or put bash back as the default /bin/sh. -- dash as #!/bin/sh introduces countless incompatibilities https://bugs.launchpad.net/bugs/141481 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 141481] Re: dash as #!/bin/sh introduces countless incompatibilities
The scripts *are* buggy. dash is POSIX-compliant, so all POSIX-compliant scripts will work with it. If they use bash-specific features, they must specify that they are to be executed by /bin/bash, rather than a general POSIX-compliant shell. ** Changed in: dash (Ubuntu) Status: New => Invalid -- dash as #!/bin/sh introduces countless incompatibilities https://bugs.launchpad.net/bugs/141481 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
