Extract usage information into a separate file.

tail.c

@@ -72,21 +72,6 @@ static int forever;
 /* If nonzero, print filename headers.  */
 static int print_headers;
 
-const char tail_usage[] =
-	"tail [OPTION] [FILE]...\n"
-#ifndef BB_FEATURE_TRIVIAL_HELP
-	"\nPrint last 10 lines of each FILE to standard output.\n"
-	"With more than one FILE, precede each with a header giving the\n"
-	"file name. With no FILE, or when FILE is -, read standard input.\n\n"
-	"Options:\n"
-	"\t-n NUM\t\tPrint last NUM lines instead of first 10\n"
-
-	"\t-f\t\tOutput data as the file grows.  This version\n"
-	"\t\t\tof 'tail -f' supports only one file at a time.\n"
-#endif
-	;
-
-
 static void write_header(const char *filename)
 {
 	static int first_file = 1;
@@ -516,25 +501,6 @@ char *program_name;
 /* Nonzero if we have ever read standard input.  */
 static int have_read_stdin;
 
-
-static const char tail_usage[] = "tail [OPTION]... [FILE]...\n"
-#ifndef BB_FEATURE_TRIVIAL_HELP
-"\nPrint last 10 lines of each FILE to standard output.\n\
-With more than one FILE, precede each with a header giving the file name.\n\
-With no FILE, or when FILE is -, read standard input.\n\
-\n\
-  -c=N[kbm]       output the last N bytes\n\
-  -f              output appended data as the file grows\n\
-  -n=N            output the last N lines, instead of last 10\n\
-  -q              never output headers giving file names\n\
-  -v              always output headers giving file names\n\
-\n\
-If the first character of N (bytes or lines) is a `+', output begins with \n\
-the Nth item from the start of each file, otherwise, print the last N items\n\
-in the file.  N bytes may be suffixed by k (x1024), b (x512), or m (1024^2).\n"
-#endif
-;
-
 static void write_header(const char *filename, const char *comment)
 {
 	static int first_file = 1;