Add README and LICENSE

[dups.git] / README.md

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+dups
+====
+
+Find duplicate files in given directory trees. Where "duplicate" is defined as
+having the same MD5 hash digest.
+
+It is roughly equivalent to the following one-liner:
+```sh
+find . -type f -exec md5sum '{}' \; | awk '{paths[$1, ++cnt[$1]] = $2} END {for (path in cnt) {n = cnt[path]; if (n > 1) {print(path, n); for (i=1; i<=n; i++) {print("    ", paths[path, i])} } } }'
+```
+
+which, when indented, looks like:
+```sh
+find . -type f -exec md5sum '{}' \; \
+| awk '
+    {
+        paths[$1, ++cnt[$1]] = $2
+    }
+    END {
+        for (path in cnt) {
+            n = cnt[path]
+            if (n > 1) {
+                print(path, n)
+                for (i=1; i<=n; i++) {
+                    print("    ", paths[path, i])
+                }
+            }
+        }
+    }'
+```
+
+and works well-enough, until you start getting weird file paths that are more
+of a pain to handle quoting for than re-writing this thing in OCaml :)
+
+Example
+-------
+After building, run `dups` on the current directory tree:
+
+```sh
+$ make
+Finished, 0 targets (0 cached) in 00:00:00.
+Finished, 5 targets (0 cached) in 00:00:00.
+
+$ ./dups .
+df4235f3da793b798095047810153c6b 2
+    "./_build/dups.ml"
+    "./dups.ml"
+d41d8cd98f00b204e9800998ecf8427e 2
+    "./_build/dups.mli"
+    "./dups.mli"
+087809b180957ce812a39a5163554502 2
+    "./_build/dups.native"
+    "./dups"
+Processed 102 files in 0.025761 seconds.
+```
+Note that the report line (`Processed 102 files in 0.025761 seconds.`) is
+written to `stderr`, so that `stdout` is safely processable by other tools.