Re: Bash not escaping escape sequences in directory names

[Chet Ramey]

On 1/23/22 6:33 PM, Josh Harcombe wrote:

> "user-controlled substitutions" was the wrong phrasing I guess, what I
> meant was I was wondering if this same sanitization principle should be
> applied to other things that could become part of your prompt while being
> controlled by someone else, (e.g. potentially the current git branch name)
> but since a) `git-check-ref-format` restricts valid branch names anyway and
> b) bash should probably only care about the PS1 built in substitutions then
> \W and \w are probably the only ones that would need to be sanitized.

If you're running a command substitution to add characters to your prompt
(such as the current git branch name), and you're concerned about those
characters corrupting the display, add something like `| cat -v' to the
command.

Likewise, if you're concerned that this is a problem, you can use something
like '$(echo $PWD | cat -v)' in your prompt instead of \w and solve it 
today. The word expansion equivalent for \W is similar.

There is a legitimate reason to filter the result of \w and \W (as well as
\s): the non-printing characters in the result can disturb readline's
redisplay.

However, you can't go too far with this. Following this train to its
logical end means that `pwd' and `cd' would have to sanitize their output,
since the same thing can happen.

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