dtree pretty-prints directory structures like this:

      |-df---------
      |-ftw--------
      |
      |            |-bin-src-
      |            |-date----
      |-gnu--------|-install-
      |            |-lib-----
|-src-|            |-libc----
      |            |-tput----
      |-misc-------
      |-patches----
      |-printf-----
      |-qterm------

It was originally written for v7 and 4.1BSD; a version that had been
partially adapted to the Berkeley Fast File System and portable
directory package appeared in mod.sources several years ago, but it
had several bugs (among the more severe, it always dumps core on some
systems).  This version fixes those and also has improved performance
and more helpful error messages.  It also works on System V; for the
benefit of System V users, I have packaged with dtree Doug Gwyn's free
reimplementation of the getcwd function that doesn't open a pipe to
/bin/pwd but determines the current directory directly; this should
help performance on those systems.
