Jilles Tjoelker <[email protected]> wrote:
> However, things like "${a-"*"}" are unspecified (in practice, the
> asterisk may either be literal or generate pathnames, depending on the
> shell). With
>
> cat <<EOF
> ${a-"*"}
> EOF
echo "${a-"*"}"
is equivalent to "echo *" for the Bourne Shell, ksh88, ksh93 and bosh.
${a-"*"} is different, as this quotes "*". Even with this,
Bourne Shell, ksh88 and bosh behave identical, only ksh93 differs.
What I have in mind for "${a-"*"}" is that there is no special treatment for '"'
in such a string and the only difference between the Bourne Shell and POSIX is
that ${a... needs to be parsed in a way that does not let the word end before
the related "}" is seen. This results in ${a- } to be treated as a single word
(and not as two words as done by the Bourne Shell) and thus permits the macro
expander to do something useful.
Jörg
--
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