mdBook does not produce any output

[gnzlbg]

I was setting uploading the simd perf-guide to the nursery in packed_simd, and executing the following command in the root directory packed_simd/:

mkdir -p target/doc
 mdbook build perf-guide --dest-dir target/doc/

produces the following output

2018-09-06 10:44:34 [INFO] (mdbook::book): Book building has started
2018-09-06 10:44:34 [INFO] (mdbook::book): Running the html backend

but the destination directory is empty:

ll target/doc
total 0
drwxr-xr-x  2 gnzlbg  staff    64B Sep  6 10:37 .
drwxr-xr-x  5 gnzlbg  staff   160B Sep  6 10:37 ..

I haven't been able to find the output book anywhere after running this command (there doesn't seem to be a doc/ or book/ directory anywhere).

So what I've ended up doing is:

cd perf-guide
mdbook build
cd -
cp -r perf-guide/book target/doc/perf-guide

instead. IIUC --dest-dir target/doc or --dest-dir target/doc/perf-guide should do what I want, but they appear to not be working.

[mattico]

If the dest-dir is a relative path, it's interpreted relative to the book's root directory. I agree that this is confusing (see #698).

I believe this is a duplicate of that issue, but I've been wrong before. Feel free to reopen.