Re: forward slash is added at end of commands in tab completion if there is a directory with the same name

On 2/26/26 9:27 PM, Martin D Kealey wrote:
> 
> 
> On Fri, 27 Feb 2026 at 04:19, Chet Ramey <[email protected] 
> <mailto:[email protected]>> wrote:
> 
>     It's ambiguous.  Both a binary in $PATH and a directory in the current
>     directory can be valid completions, since bash completion (and readline)
>     allows you to build a relative pathname by completing a directory at a
>     time.
> 
>     Because it's ambiguous, the name exists as a directory in the current
>     directory, and you have the `mark-directories' readline variable set,
>     readline appends the slash.
> 
> 
> I can follow this logic to see why it behaves as  it does, except that it 
> it's inconsistent.
> 
> If you have the full suite of vim installed then Bash shows a list like this:
> vim        vim.basic  vim.gtk3   vim.tiny   vimdiff    vimdot     vimplate 
>    vimtutor
> 
> Add a directory «vim» with «mark-directories» is in effect, and instead you 
> get:
> vim/       vim.basic  vim.gtk3   vim.tiny   vimdiff    vimdot     vimplate 
>    vimtutor
> 
> which differs only in the addition of a trailing slash.

Yes. It's ambiguous. When presented with `vim' in the (deduplicated) list
of possible completions, readline has to choose which interpretation to
take. Since `mark-directories' is set, and this is a directory, it chooses
to append the slash.

> However, when you only have the vim directory and the vim command, with no 
> other commands machines that prefix, pressing tab shows a single-item list
> vim
> which has no slash, regardless of «mark-directories».

Since there is only a single completion, bash can (and does) special-case
this and tell readline not to append the slash. It wouldn't be appropriate
to do this for more than a single completion, since the appending applies
to every possible completion -- either you append, or you don't, to each
one.

> I contend that «vim» and «vim/» should count as separate completions; this 
> is consistent with:

You'd like readline to annotate the completion list with additional
application-specific information, which is nice, but would have to be done
via an additional data structure.


> I suggest that these inconsistencies (and the original bug report) would be 
> resolved by showing both «vim» and «vim/» in the displayed list; in effect, 
> mark-directories would act to modify each element as it's added to the list 
> of completions, rather acting when when each item is displayed or used to 
> extend the completion.

That's an idea, but it would have to interact with the other annotations
readline does.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
		 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    [email protected]    http://tiswww.cwru.edu/~chet/

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