cc: [email protected]
Subject: Re: [ast-users] ksh bugs?
--------
Here are the responses to the first three of your problem reports. More
will follow:
> Some of these may be expected behavior.
> In each case I'd like to know if that's the case.
>
> 1)
> This worked up through the 2009-05-01 version:
> [[ \] == [x\]y] ]] && print ok
> It no longer works as of 2009-12-24.
This change was need in order to align with the posix sh spec for [...].
the last sentence is the one in play:
A bracket expression is either a matching list expression
or a non-matching list expression. It consists of one or
more expressions: collating elements, collating symbols,
equivalence classes, character classes, or range
expressions. The <right-square-bracket> ( ']' ) shall lose
its special meaning and represent itself in a bracket
expression if it occurs first in the list (after an initial
<circumflex> ( '^' ), if any). Otherwise, it shall
terminate the bracket expression, unless it appears in a
collating symbol (such as "[.].]" ) or is the ending
<right-square-bracket> for a collating symbol, equivalence
class, or character class. The special characters '.' , '*'
, '[' , and '\\' ( <period>, <asterisk>,
<left-square-bracket>, and <backslash>, respectively) shall
lose their special meaning within a bracket expression.
>
> 2)
> time | cat
> -ksh: syntax error: `|' unexpected
time is not a simple command. It is reserved would that is
optionally followed by a pipeline. Since time is followed by
| cat
and | cat is not a pipeline, this is a syntax error.
>
> 3)
> $ touch \#foo
> $ ls #<tab>
> expands to
> $ ls #foo
> I think a leading # in a word should be escaped in tab expansion.
>
This will be changed in ksh93u for insert a \ in front of file names
beginning with #.
> 7)
> This gives a memory fault:
> output=$(printf "%10000s"); [[ $output == *(?) ]]
The memory fault is a stack overflow. You can use ulimit -s to increase
the stack size and prevent the memory fault. However, the question is
why it required as much stack as it did and this is being investigated.
>
> 8)
> echo foo | od /dev/fd/0
> od: /dev/fd/0: No such device or address
This is because Linux doesn't support /dev/fd/0 for socketpair which
is used by ksh93 for pipelines. I believe that this is a Linux bug.
> And perhaps related:
> function ft { /bin/echo foo; }; : $(od <(ft))
> foo
>
This has been fixed since ksh93 now uses pipes for process substitution.
David Korn
[email protected]
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