Enhance UI, preserve timestamps

Removed my oh-so-clever "shadowdir" and "shadowfile" concepts for
    the directory to be examined for potential deduplication. Instead
    we call them subject directories and subject files, because they
    are subject to our process.

    Now creates a temporary file, removed on exit, as our temporary
    access and modification time holder. When replacing a file with a
    hard link, we first copy the atime/mtime of its directory to the
    temporary file. THEN we perform the link. After the link, we
    restore the original atime/mtime of the enclosing directory from
    the temporary file. This is useful for backups, where we do not
    want the directories to have newer timestamps (timestamps matching
    the date/time that we run deduplication, because creating the link
    counts as a modification of the directory).

dirdedupe.sh

@@ -1,11 +1,6 @@
 #!/usr/bin/env bash
 
-# BITSC LICENSE NOTICE (MODIFIED ISC LICENSE)
+# Copyright (c) 2023 Joshua Lee Ockert <torstenvl@gmail.com>
-#
-# 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
@@ -25,22 +20,19 @@ DIRECTORY DE-DUPLICATOR
 
 USAGE
 
-    dirdedupe.sh [--execute] masterdir shadowdir
+    dirdedupe.sh [--execute] masterdir subjectdir
 
 DESCRIPTION
 
-    For each file in shadowdir, replace it with a hard link to the matching file
+    For each file in subjectdir, replace it with a hard link to the matching
-    (if any) in masterdir.  A file will be considered a match if, and only if,
+    file (if any) in masterdir.  A file will be considered a match if, and
-    it shares the same file name, relative path, and contents.
+    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. 
 
-MISC
-
-    The name of this utility is pronounced "dirty dupe."
 "
 }
 
@@ -61,41 +53,55 @@ if [ ! $# -eq 2 ]; then
   echo && echo "Wrong number of arguments!" && printusage && exit
 else
   masterdir=$1
-  shadowdir=$2
+  subjectdir=$2
   if [ ! -d "${masterdir}" ]; then
     echo && echo "${masterdir} is not a directory!" && printusage && exit
-  elif [ ! -d "${shadowdir}" ]; then
+  elif [ ! -d "${subjectdir}" ]; then
-    echo && echo "${shadowdir} is not a directory!" && printusage && exit
+    echo && echo "${subjectdir} is not a directory!" && printusage && exit
   fi
 fi
 
+############################################################################
+##            MAKE A TEMPORARY FILE FOR PRESERVING TIMESTAMPS             ##
+############################################################################
+TEMPFILE = $(mktemp)
+trap "rm -f ${TEMPFILE}" EXIT
 
 ############################################################################
 ##                    HARDLINK THE DUPLICATES (OR NOT)                    ##
 ############################################################################
-find "${shadowdir}" -print0 | while read -d $'\0' shadowfile
+find "${subjectdir}" -print0 | while read -d $'\0' subjectfile
 do
-    if [ -f "${shadowfile}" ]; then
+    if [ -f "${subjectfile}" ]; then
-      masterfile="${shadowfile/#${shadowdir}/${masterdir}}"
+        masterfile="${subjectfile/#${subjectdir}/${masterdir}}"
         if [ -f "${masterfile}" ]; then
-        if [ "${shadowfile}" -ef "${masterfile}" ]; then
+            if [ ! "${subjectfile}" -ef "${masterfile}" ]; then
-          echo "ID   \"${masterfile}\" <-> \"${shadowfile}\""
+                cmp -s "${masterfile}" "${subjectfile}"
-        else
-          cmp -s "${masterfile}" "${shadowfile}"
                 if [ $? -eq 0 ]; then
                     if [ $REALLYRUN -gt 0 ]; then
-              echo "LINK \"${masterfile}\" <-- \"${shadowfile}\""
+                        echo "LINK \"${masterfile}\" <-- \"${subjectfile}\""
-              ln -Pf "${masterfile}" "${shadowfile}"
+                        # Store the mtime/atime of subject file's directory
+                        TEMPSUBJDIR=`dirname "${subjectfile}"`
+                        #touch -r "${TEMPSUBJDIR}" "${TEMPFILE}"
+                        # Link the subject file to the corresponding file in
+                        # the master directory
+                        ln -Pf "${masterfile}" "${subjectfile}"
+                        # Restore the mtime/atime of subject file's directory
+                        #touch -r "${TEMPFILE}" "${TEMPSUBJDIR}"
                     else
-              echo "HYPO \"${masterfile}\" <~~ \"${shadowfile}\""
+                        echo "HYPO \"${masterfile}\" <~~ \"${subjectfile}\""
+                        TEMPSUBJDIR=`dirname "${subjectfile}"`
+                        echo "   Saving atime/mtime of |${TEMPSUBJDIR}|"
                     fi
-          else
+                #else
-            echo "MOD  \"${masterfile}\" <X> \"${shadowfile}\""
+                    #echo "MOD  \"${masterfile}\" <X> \"${subjectfile}\""
-          fi # end check for file equality
+                fi #END check for files being the same
-        fi # end check for inode equality
+            #else
-      else
+                #echo "ID   \"${masterfile}\" <-> \"${subjectfile}\""
-        echo "NEW  \"${shadowfile}\" "
+            fi # END check for inode equality
-      fi # end check if master file exists
+        #else
+            #echo "NEW  \"${subjectfile}\" "
+        fi # END check if master file exists
     fi
 done