cp/mv: add --no-clobber (-n) option to not overwrite target

* src/cp.c (usage): Show new option -n in --help.
(main): Handle new option -n.
* src/mv.c (usage): Show new option -n in --help.
(main): Handle new option -n.
* doc/coreutils.texi: Document new cp/mv option -n.
* tests/cp/cp-i: Add tests for -f, -i and -n options.
* tests/mv/mv-n: New test for mv -n.
* tests/Makefile.am: Add test mv/mv-n to the list.
* NEWS: Mention the change.

tests/Makefile.am

@@ -379,6 +379,7 @@ TESTS =						\
   mv/into-self-3				\
   mv/into-self-4				\
   mv/leak-fd					\
+  mv/mv-n					\
   mv/mv-special-1				\
   mv/no-target-dir				\
   mv/part-fail					\

tests/cp/cp-i

@@ -31,4 +31,40 @@ fail=0
 # coreutils 6.2 cp would neglect to prompt in this case.
 echo n | cp -iR a b 2>/dev/null || fail=1
 
+# test miscellaneous combinations of -f -i -n parameters
+touch c d || framework_failure
+echo "\`c' -> \`d'" > out_copy
+> out_empty
+
+# ask for overwrite, answer no
+echo n | cp -vi  c d 2>/dev/null > out1 || fail=1
+compare out1 out_empty || fail=1
+
+# ask for overwrite, answer yes
+echo y | cp -vi  c d 2>/dev/null > out2 || fail=1
+compare out2 out_copy  || fail=1
+
+# -i wins over -n
+echo y | cp -vni c d 2>/dev/null > out3 || fail=1
+compare out3 out_copy  || fail=1
+
+# -n wins over -i
+echo y | cp -vin c d 2>/dev/null > out4 || fail=1
+compare out4 out_empty || fail=1
+
+# ask for overwrite, answer yes
+echo y | cp -vfi c d 2>/dev/null > out5 || fail=1
+compare out5 out_copy  || fail=1
+
+# do not ask, prevent from overwrite
+echo n | cp -vfn c d 2>/dev/null > out6 || fail=1
+compare out6 out_empty || fail=1
+
+# do not ask, prevent from overwrite
+echo n | cp -vnf c d 2>/dev/null > out7 || fail=1
+compare out7 out_empty || fail=1
+
+# options --backup and --no-clobber are mutually exclusive
+cp -bn c d 2>/dev/null && fail=1
+
 Exit $fail

tests/mv/mv-n

@@ -0,0 +1,62 @@
+#!/bin/sh
+# Test whether mv -n works as documented (not overwrite target).
+
+# Copyright (C) 2006-2008 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+if test "$VERBOSE" = yes; then
+  set -x
+  mv --version
+fi
+
+. $srcdir/test-lib.sh
+
+fail=0
+
+# test miscellaneous combinations of -f -i -n parameters
+touch a b || framework_failure
+echo "\`a' -> \`b'" > out_move
+> out_empty
+
+# ask for overwrite, answer no
+touch a b || framework_failure
+echo n | mv -vi a b 2>/dev/null > out1 || fail=1
+compare out1 out_empty || fail=1
+
+# ask for overwrite, answer yes
+touch a b || framework_failure
+echo y | mv -vi a b 2>/dev/null > out2 || fail=1
+compare out2 out_move || fail=1
+
+# -n wins (as the last option)
+touch a b || framework_failure
+echo y | mv -vin a b 2>/dev/null > out3 || fail=1
+compare out3 out_empty || fail=1
+
+# -n wins (as the last option)
+touch a b || framework_failure
+echo y | mv -vfn a b 2>/dev/null > out4 || fail=1
+compare out4 out_empty || fail=1
+
+# -n wins (as the last option)
+touch a b || framework_failure
+echo y | mv -vifn a b 2>/dev/null > out5 || fail=1
+compare out5 out_empty || fail=1
+
+# options --backup and --no-clobber are mutually exclusive
+touch a || framework_failure
+mv -bn a b 2>/dev/null && fail=1
+
+Exit $fail