How do I recursively list all directories at a location, breadth-first?
If you want to do it using standard tools, the following pipeline should work:
find . -type d | perl -lne 'print tr:/::, " $_"' | sort -n | cut -d' ' -f2
That is,
- find and print all the directories here in depth first order
- count the number of slashes in each directory and prepend it to the path
- sort by depth (i.e., number of slashes)
- extract just the path.
To limit the depth found, add the -maxdepth argument to the find command.
If you want the directories listed in the same order that find output them, use "sort -n -s" instead of "sort -n"; the "-s" flag stabilizes the sort (i.e., preserves input order among items that compare equally).
The find command supports -printf option which recognizes a lot of placeholders.
One such placeholder is %d which renders the depth of given path, relative to where find started.
Therefore you can use following simple one-liner:
find -type d -printf '%d\t%P\n' | sort -r -nk1 | cut -f2-
It is quite straightforward, and does not depend on heavy tooling like perl.
How it works:
- it internally generates list of files, each rendered as a two-field line
- the first field contains the depth, which is used for (reverse) numerical sorting, and then cut away
- resulting is simple file listing, one file per line, in the deepest-first order