+ { $doit $mvcmd -f "$dsttmp" "$dstdir/$dstfile" 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
+ # support -f.
+
+ # Now remove or move aside any old file at destination location.
+ # We try this two ways since rm can't unlink itself on some
+ # 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.
+ {
+ if test -f "$dstdir/$dstfile"; then
+ $doit $rmcmd -f "$dstdir/$dstfile" 2>/dev/null \
+ || $doit $mvcmd -f "$dstdir/$dstfile" "$rmtmp" 2>/dev/null \
+ || {
+ echo "$0: cannot unlink or rename $dstdir/$dstfile" >&2
+ (exit 1); exit 1
+ }
+ else
+ :
+ fi
+ } &&
+
+ # Now rename the file to the real destination.
+ $doit $mvcmd "$dsttmp" "$dstdir/$dstfile"
+ }
+ }
+ fi || { (exit 1); exit 1; }