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.

2 files changed, 35 insertions, 6 deletions

diff --git a/src/cp.c b/src/cp.c
index 8e349658a..191f73e7b 100644
--- a/src/cp.c
+++ b/src/cp.c
@@ -1,5 +1,5 @@
 /* cp.c  -- file copying (main routines)
-   Copyright (C) 89, 90, 91, 1995-2008 Free Software Foundation, Inc.
+   Copyright (C) 89, 90, 91, 1995-2009 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
@@ -116,6 +116,7 @@ static struct option const long_opts[] =
   {"force", no_argument, NULL, 'f'},
   {"interactive", no_argument, NULL, 'i'},
   {"link", no_argument, NULL, 'l'},
+  {"no-clobber", no_argument, NULL, 'n'},
   {"no-dereference", no_argument, NULL, 'P'},
   {"no-preserve", required_argument, NULL, NO_PRESERVE_ATTRIBUTES_OPTION},
   {"no-target-directory", no_argument, NULL, 'T'},
@@ -167,8 +168,10 @@ Mandatory arguments to long options are mandatory for short options too.\n\
 "), stdout);
       fputs (_("\
   -f, --force                  if an existing destination file cannot be\n\
-                                 opened, remove it and try again\n\
-  -i, --interactive            prompt before overwrite\n\
+                                 opened, remove it and try again (redundant if\n\
+                                 the -n option is used)\n\
+  -i, --interactive            prompt before overwrite (overrides a previous -n\n\
+                                  option)\n\
   -H                           follow command-line symbolic links in SOURCE\n\
 "), stdout);
       fputs (_("\
@@ -176,6 +179,8 @@ Mandatory arguments to long options are mandatory for short options too.\n\
   -L, --dereference            always follow symbolic links in SOURCE\n\
 "), stdout);
       fputs (_("\
+  -n, --no-clobber             do not overwrite an existing file (overrides\n\
+                                 a previous -i option)\n\
   -P, --no-dereference         never follow symbolic links in SOURCE\n\
 "), stdout);
       fputs (_("\
@@ -894,7 +899,7 @@ main (int argc, char **argv)
      we'll actually use backup_suffix_string.  */
   backup_suffix_string = getenv ("SIMPLE_BACKUP_SUFFIX");
 
-  while ((c = getopt_long (argc, argv, "abdfHilLprst:uvxPRS:T",
+  while ((c = getopt_long (argc, argv, "abdfHilLnprst:uvxPRS:T",
 			   long_opts, NULL))
 	 != -1)
     {
@@ -950,6 +955,10 @@ main (int argc, char **argv)
 	  x.dereference = DEREF_ALWAYS;
 	  break;
 
+	case 'n':
+	  x.interactive = I_ALWAYS_NO;
+	  break;
+
 	case 'P':
 	  x.dereference = DEREF_NEVER;
 	  break;
@@ -1050,6 +1059,13 @@ main (int argc, char **argv)
       usage (EXIT_FAILURE);
     }
 
+  if (make_backups && x.interactive == I_ALWAYS_NO)
+    {
+      error (0, 0,
+	     _("options --backup and --no-clobber are mutually exclusive"));
+      usage (EXIT_FAILURE);
+    }
+
   if (backup_suffix_string)
     simple_backup_suffix = xstrdup (backup_suffix_string);
 
diff --git a/src/mv.c b/src/mv.c
index 98309a412..a5ab95dcf 100644
--- a/src/mv.c
+++ b/src/mv.c
@@ -1,5 +1,5 @@
 /* mv -- move or rename files
-   Copyright (C) 86, 89, 90, 91, 1995-2008 Free Software Foundation, Inc.
+   Copyright (C) 86, 89, 90, 91, 1995-2009 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
@@ -62,6 +62,7 @@ static struct option const long_options[] =
   {"backup", optional_argument, NULL, 'b'},
   {"force", no_argument, NULL, 'f'},
   {"interactive", no_argument, NULL, 'i'},
+  {"no-clobber", no_argument, NULL, 'n'},
   {"no-target-directory", no_argument, NULL, 'T'},
   {"strip-trailing-slashes", no_argument, NULL, STRIP_TRAILING_SLASHES_OPTION},
   {"suffix", required_argument, NULL, 'S'},
@@ -296,6 +297,8 @@ Mandatory arguments to long options are mandatory for short options too.\n\
   -b                           like --backup but does not accept an argument\n\
   -f, --force                  do not prompt before overwriting\n\
   -i, --interactive            prompt before overwrite\n\
+  -n, --no-clobber             do not overwrite an existing file\n\
+If you specify more than one of -i, -f, -n, only the final one takes effect.\n\
 "), stdout);
       fputs (_("\
       --strip-trailing-slashes  remove any trailing slashes from each SOURCE\n\
@@ -358,7 +361,7 @@ main (int argc, char **argv)
      we'll actually use backup_suffix_string.  */
   backup_suffix_string = getenv ("SIMPLE_BACKUP_SUFFIX");
 
-  while ((c = getopt_long (argc, argv, "bfit:uvS:T", long_options, NULL))
+  while ((c = getopt_long (argc, argv, "bfint:uvS:T", long_options, NULL))
 	 != -1)
     {
       switch (c)
@@ -374,6 +377,9 @@ main (int argc, char **argv)
 	case 'i':
 	  x.interactive = I_ASK_USER;
 	  break;
+	case 'n':
+	  x.interactive = I_ALWAYS_NO;
+	  break;
 	case STRIP_TRAILING_SLASHES_OPTION:
 	  remove_trailing_slashes = true;
 	  break;
@@ -446,6 +452,13 @@ main (int argc, char **argv)
 	       quote (file[n_files - 1]));
     }
 
+  if (make_backups && x.interactive == I_ALWAYS_NO)
+    {
+      error (0, 0,
+	     _("options --backup and --no-clobber are mutually exclusive"));
+      usage (EXIT_FAILURE);
+    }
+
   if (backup_suffix_string)
     simple_backup_suffix = xstrdup (backup_suffix_string);