@@ -1,9 +1,9 @@
 #!/bin/sh
 # install - install a program, script, or datafile
 
-scriptversion=2020-07-26.22; # UTC
+scriptversion=2020-11-14.01; # UTC
 
 # This originates from X11R5 (mit/util/scripts/install.sh), which was
 # later released in X11R6 (xc/config/util/install.sh) with the
 # following copyright and license.
 #
@@ -71,10 +71,11 @@
 
 # Create dirs (including intermediate dirs) using mode 755.
 # This is like GNU 'install' as of coreutils 8.32 (2020).
 mkdir_umask=22
 
+backupsuffix=
 chgrpcmd=
 chmodcmd=$chmodprog
 chowncmd=
 mvcmd=$mvprog
 rmcmd="$rmprog -f"
@@ -101,23 +102,32 @@
 Options:
      --help     display this help and exit.
      --version  display version info and exit.
 
   -c            (ignored)
-  -C            install only if different (preserve the last data modification time)
+  -C            install only if different (preserve data modification time)
   -d            create directories instead of installing files.
   -g GROUP      $chgrpprog installed files to GROUP.
   -m MODE       $chmodprog installed files to MODE.
   -o USER       $chownprog installed files to USER.
+  -p            pass -p to $cpprog.
   -s            $stripprog installed files.
-  -S OPTION     $stripprog installed files using OPTION.
+  -S SUFFIX     attempt to back up existing files, with suffix SUFFIX.
   -t DIRECTORY  install into DIRECTORY.
   -T            report an error if DSTFILE is a directory.
 
 Environment variables override the default commands:
   CHGRPPROG CHMODPROG CHOWNPROG CMPPROG CPPROG MKDIRPROG MVPROG
   RMPROG STRIPPROG
+
+By default, rm is invoked with -f; when overridden with RMPROG,
+it's up to you to specify -f if you want it.
+
+If -S is not specified, no backups are attempted.
+
+Email bug reports to bug-automake@gnu.org.
+Automake home page: https://www.gnu.org/software/automake/
 "
 
 while test $# -ne 0; do
   case $1 in
     -c) ;;
@@ -140,13 +150,15 @@
         shift;;
 
     -o) chowncmd="$chownprog $2"
         shift;;
 
+    -p) cpprog="$cpprog -p";;
+
     -s) stripcmd=$stripprog;;
 
-    -S) stripcmd="$stripprog $2"
+    -S) backupsuffix="$2"
         shift;;
 
     -t)
         is_target_a_directory=always
         dst_arg=$2
@@ -261,10 +273,14 @@
   if test -n "$dir_arg"; then
     dst=$src
     dstdir=$dst
     test -d "$dstdir"
     dstdir_status=$?
+    # Don't chown directories that already exist.
+    if test $dstdir_status = 0; then
+      chowncmd=""
+    fi
   else
 
     # Waiting for this to be detected by the "$cpprog $src $dsttmp" command
     # might cause directories to be created, which would be especially bad
     # if $src (and thus $dsttmp) contains '*'.
@@ -475,10 +491,17 @@
        test "$old" = "$new" &&
        $cmpprog "$dst" "$dsttmp" >/dev/null 2>&1
     then
       rm -f "$dsttmp"
     else
+      # If $backupsuffix is set, and the file being installed
+      # already exists, attempt a backup.  Don't worry if it fails,
+      # e.g., if mv doesn't support -f.
+      if test -n "$backupsuffix" && test -f "$dst"; then
+        $doit $mvcmd -f "$dst" "$dst$backupsuffix" 2>/dev/null
+      fi
+
       # Rename the file to the real destination.
       $doit $mvcmd -f "$dsttmp" "$dst" 2>/dev/null ||
 
       # The rename failed, perhaps because mv can't rename something else
       # to itself, or perhaps because mv is so ancient that it does not
@@ -489,13 +512,13 @@
         # systems and the destination file might be busy for other
         # reasons.  In this case, the final cleanup might fail but the new
         # file should still install successfully.
         {
           test ! -f "$dst" ||
-          $doit $rmcmd -f "$dst" 2>/dev/null ||
+          $doit $rmcmd "$dst" 2>/dev/null ||
           { $doit $mvcmd -f "$dst" "$rmtmp" 2>/dev/null &&
-            { $doit $rmcmd -f "$rmtmp" 2>/dev/null; :; }
+            { $doit $rmcmd "$rmtmp" 2>/dev/null; :; }
           } ||
           { echo "$0: cannot unlink or rename $dst" >&2
             (exit 1); exit 1
           }
         } &&