Initial Commit

This initial commit includes a directory deduplicator (for thinning out
Time Machine snapshots) and an automatic tool to detect and apply the
necessary metadata for a successful tmutil inherit (needed when you
want to use a backup drive with a new computer, for example).

dirdedupe.sh

@@ -0,0 +1,87 @@
+#!/usr/bin/env bash
+
+# BITSC LICENSE NOTICE (MODIFIED ISC LICENSE)
+#
+# DIRECTORY DE-DUPLICATION ("Dirty Dupe")
+#
+# Copyright (c) 2022 Lee Ockert <torstenvl@gmail.com>
+#                    https://github.com/torstenvl
+#
+# THIS WORK IS PROVIDED "AS IS" WITH NO WARRANTY OF ANY KIND. THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY, FITNESS, NON-INFRINGEMENT, AND TITLE ARE
+# EXPRESSLY DISCLAIMED. NO AUTHOR SHALL BE LIABLE UNDER ANY THEORY OF LAW
+# FOR ANY DAMAGES OF ANY KIND RESULTING FROM THE USE OF THIS WORK.
+#
+# Permission to use, copy, modify, and/or distribute this work for any
+# purpose is hereby granted, provided this notice appears in all copies.
+
+
+############################################################################
+##                  FUNCTION TO PRINT USAGE INSTRUCTIONS                  ##
+############################################################################
+printusage() {
+    echo "
+DIRECTORY DE-DUPLICATION (\"Dirty Dupe\")
+
+${0} [--execute] masterdir shadowdir
+
+For each file in shadowdir, replace it with a hard link to the matching file
+(if any) in masterdir.  A file will be considered a match if, and only if, it
+shares the same file name, relative path, and contents.
+
+OPTIONS
+
+    --execute  Actually remove and link duplicate files. By default, this
+               program runs in test mode. 
+"
+}
+
+
+############################################################################
+##                   PARSE & MAKE SENSE OF COMMAND LINE                   ##
+############################################################################
+
+# CHECK FOR THE EXECUTE FLAG (DEFAULT IS TESTING-ONLY MODE)
+REALLYRUN=0
+if [ "${1}" == "--execute" ]; then
+  REALLYRUN=1
+  shift
+fi
+
+# MAKE SURE WE HAVE THE RIGHT NUMBER OF ARGUMENTS AND THEY'RE VALID
+if [ ! $# -eq 2 ]; then
+  echo && echo "Wrong number of arguments!" && printusage && exit
+else
+  masterdir=$1
+  shadowdir=$2
+  if [ ! -d "${masterdir}" ]; then
+    echo && echo "${masterdir} is not a directory!" && printusage && exit
+  elif [ ! -d "${shadowdir}" ]; then
+    echo && echo "${shadowdir} is not a directory!" && printusage && exit
+  fi
+fi
+
+
+############################################################################
+##                    HARDLINK THE DUPLICATES (OR NOT)                    ##
+############################################################################
+find "${shadowdir}" -print0 | while read -d $'\0' shadowfile
+do
+    if [ -f "${shadowfile}" ]; then
+      masterfile="${shadowfile/#${shadowdir}/${masterdir}}"
+      if [ -f "${masterfile}" ]; then
+        cmp -s "${masterfile}" "${shadowfile}"
+        if [ $? -eq 0 ]; then
+          if [ $REALLYRUN -gt 0 ]; then
+            echo "Linking \"${masterfile}\" <-- \"${shadowfile}\""
+            ln -Pf "${masterfile}" "${shadowfile}"
+          else
+            echo "NOT linking \"${masterfile}\" <-- \"${shadowfile}\""
+          fi
+        fi
+      fi
+    fi
+done
+
+exit
+