"W. Trevor King" <wking@xxxxxxxxxx> writes:
> I'm not 100% convinced about this, because the git-rebase.sh uses:
>
> "$GIT_DIR/hooks/pre-rebase" ${1+"$@"}
>
> I haven't been able to find documentation for the ${1+"$@"} syntax.
> Is it in POSIX? It's not in the Bash manual:
[...]
> In my local tests, it seems equivalent to "$@".
It's definitely in the bash manual and POSIX[1]: it's a special case of
the ${parameter+word} expansion.
${parameter:+word}
Use Alternate Value. If parameter is null or unset, nothing is
substituted, otherwise the expansion of word is substituted.
plus
... bash tests for a parameter that is unset or null. Omitting the
colon results in a test only for a parameter that is unset.
IIRC this particular usage was designed to suppress warnings about unset
variables.
Footnotes:
[1] http://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html
--
Thomas Rast
trast@{inf,student}.ethz.ch
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