Re: find -delete .. Do What I Mean?

[Matthijs De Smedt]

On 9/7/07, Eric Blake <address@hidden> wrote:

> > Maybe something can be added under "Expressions" explaining exactly how
> find
> > interprets expressions.
>
> Where do you propose adding it?  There is already information there - for
> each file name being visited, find evaluates the expression from left to
> right until it hits something that evaluates to false.  -delete evaluates
> to true if it successfully deletes anything, so by listing it first, you
> are asking find to delete a file, and if it fails, then do the next part
> of the expression (which finally does name filtering).  Usually, you want
> to do the filtering first (for example, -iname returns false if the file
> name does not match the pattern), then only -delete what is left.  Maybe
> what we should add is a sentence to -delete:
>
> Note that -delete is usually placed at the end of an expression, after all
> earlier tests have filtered the list of which files to delete.


Yes. If I would've seen that hint I would have thought twice about find's
syntax before running the delete.

I realize now that I didn't read the sentence in the manual about expression
parsing because it was under "description", not under "expressions" (where I
expected it). I don't blame the manpage for not conforming to my
expectations. But perhaps some hints in the later sections will prevent
future mistakes like mine.

> ps. Why is "find -iname *-1*.jpg" invalid? I didn't explicitly indicate
> the
> > path to search so find assumes the working directory.
>
> Because you did not protect it from filename expansion by the shell.  If
> your current directory happens to have a single file that matches that
> pattern, then you are really invoking "find -iname myfile-1.jpg", which
> does not find everything based on the pattern.  And if your current
> directory happens to have two or more files that match the pattern, you
> have just given find a syntax error, since in "find -iname f1-1.jpg
> f2-1.jpg", f2-1.jpg falls in the position of an expected expression, but
> does not match any known expression.  You probably meant:
>
> find -iname "*-1*.jpg"


Ah, thanks. I didn't know a shell would do expansion there.

Matthijs