null separated ls output option

[rain1]

Hello

Please consider accepting this patch I wrote which adds a new -0 feature 
to ls.

This emits the entries separated by null bytes (similar to 
/proc/$PID/cmdline) which creates a completely unambiguous and simple 
output format that doesn't involve any quotation or escaping (like ls -1 
and ls -Q1) by using a separator which cannot occur inside a filename 
(\0). Inside emacs eshell for example, the output is nicely human 
readable with the null separator displayed as ^@.

diff -Naur '--exclude=*~' coreutils-8.27/src/ls.c 
coreutils-8.27-ls-0-patch/src/ls.c
--- coreutils-8.27/src/ls.c     2017-01-21 14:53:43.000000000 +0000
+++ coreutils-8.27-ls-0-patch/src/ls.c	2017-05-31 22:05:43.782177300 
+0000
@@ -410,6 +410,7 @@
   {
     long_format,               /* -l and other options that imply -l */
     one_per_line,              /* -1 */
+    null_separated,            /* -0 */
     many_per_line,             /* -C */
     horizontal,                        /* -x */
     with_commas                        /* -m */
@@ -875,12 +876,12 @@
 static char const *const format_args[] =
 {
   "verbose", "long", "commas", "horizontal", "across",
-  "vertical", "single-column", NULL
+  "vertical", "single-column", "null-separated", NULL
 };
 static enum format const format_types[] =
 {
   long_format, long_format, with_commas, horizontal, horizontal,
-  many_per_line, one_per_line
+  many_per_line, one_per_line, null_separated
 };
 ARGMATCH_VERIFY (format_args, format_types);

@@ -1753,7 +1754,7 @@
     {
       int oi = -1;
       int c = getopt_long (argc, argv,
-                           
"abcdfghiklmnopqrstuvw:xABCDFGHI:LNQRST:UXZ1",
+                           
"abcdfghiklmnopqrstuvw:xABCDFGHI:LNQRST:UXZ10",
                            long_options, &oi);
       if (c == -1)
         break;
@@ -1949,6 +1950,10 @@
             format = one_per_line;
           break;

+        case '0':
+          format = null_separated;
+          break;
+
         case AUTHOR_OPTION:
           print_author = true;
           break;
@@ -2763,7 +2768,8 @@
                  ls uses constant memory while processing the entries 
of
                  this directory.  Useful when there are many (millions)
                  of entries in a directory.  */
-              if (format == one_per_line && sort_type == sort_none
+              if ((format == one_per_line || format == null_separated)
+                     && sort_type == sort_none
                       && !print_block_size && !recursive)
                 {
                   /* We must call sort_files in spite of
@@ -3770,6 +3776,14 @@
         }
       break;

+    case null_separated:
+      for (i = 0; i < cwd_n_used; i++)
+        {
+          print_file_name_and_frills (sorted_file[i], 0);
+          putchar ('\0');
+        }
+      break;
+
     case many_per_line:
       if (! line_length)
         print_with_separator (' ');
@@ -5150,7 +5164,8 @@
   -x                         list entries by lines instead of by 
columns\n\
   -X                         sort alphabetically by entry extension\n\
   -Z, --context              print any security context of each file\n\
-  -1                         list one file per line.  Avoid '\\n' with 
-q or -b\
+  -1                         list one file per line.  Avoid '\\n' with 
-q or -b\n\
+  -0                         separate entries by a null byte.\n\
 \n\
 "), stdout);
       fputs (HELP_OPTION_DESCRIPTION, stdout);