On Thu, Mar 24, 2022 at 11:12:25AM -0400, Zachary Santer wrote:
> I'm consulting the online manual
> <https://www.gnu.org/software/bash/manual/html_node/index.html>, so if
> you're looking for a version number, that would be 5.1.
>
> I just now looked at doc/bash.pdf in the git repo on Savannah. No info on
> appending is present under bash-5.2-testing or devel.
> > Talking about the lines with "+=", obviously. I only learned I could
> > do this when I found it in existing code.
If you search the man page for += you can find this paragraph:
In the context where an assignment statement is assigning a value to a
shell variable or array index, the += operator can be used to append to
or add to the variable's previous value. This includes arguments to
builtin commands such as declare that accept assignment statements
(declaration commands). When += is applied to a variable for which the
integer attribute has been set, value is evaluated as an arithmetic ex‐
pression and added to the variable's current value, which is also eval‐
uated. When += is applied to an array variable using compound assign‐
ment (see Arrays below), the variable's value is not unset (as it is
when using =), and new values are appended to the array beginning at
one greater than the array's maximum index (for indexed arrays) or
added as additional key-value pairs in an associative array. When ap‐
plied to a string-valued variable, value is expanded and appended to
the variable's value.
The manual is not meant to be a tutorial. It's a reference. Information
may be in a different place than you expected, because things are
typically not repeated more than once. (The man page is already extremely
long, and repeating things would make it even bigger.)
