Hello,
This concern:
https://www.gnu.org/software/bash/manual/bash.html#Shell-Parameter-Expansion
In the bash documentation, section “shell parameter expansion,” in the
paragraph “${parameter:-word},” the example given uses
${parameter-word}
which is a Bourne Shell compatible expansion but behaves differently
for defined but empty parameters. For greater clarity, shouldn't we
write the following documentation (Please excuse the RST syntax):
``${parameter:-word}``
----------------------
If parameter is unset or null, the expansion of word is substituted.
Otherwise, the value of parameter is substituted.
::
$ v=123
$ echo ${v:-unset}
123
$ e=''
$ echo ${e:-unset}
unset
$ echo ${u:-unset}
unset
``${parameter-word}``
---------------------
If parameter is unset, the expansion of word is substituted. Otherwise,
the value of parameter is substituted.
This differs from ``${parameter:-word}`` in the case where
``parameter`` is set but not null.
This expansion comes from Bourne-Shell.
::
$ v=123
$ echo ${v:-unset}
123
$ e=''
$ echo ${e:-unset}
$ echo ${u:-unset}
unset
P.-S. This is my first report to a GNU project. Please point out any
important best practices that I have not followed.
--
Alexis Reynouard <[email protected]>
