nicer disklabel -p

[Ted Unangst]

1.  accept capital letters too, like the interactive -E command does.
2.  usage() is not the most appropriate error response.  be more helpful.

Index: disklabel.c
===================================================================
RCS file: /home/tedu/cvs/src/sbin/disklabel/disklabel.c,v
retrieving revision 1.166
diff -u -r1.166 disklabel.c
--- disklabel.c 30 Jun 2010 23:44:06 -0000      1.166
+++ disklabel.c 8 Aug 2010 05:07:02 -0000
@@ -188,10 +188,12 @@
                        op = WRITE;
                        break;
                case 'p':
-                       if (strchr("bckmgt", optarg[0]) == NULL ||
-                           optarg[1] != '\0')
-                               usage();
-                       print_unit = optarg[0];
+                       if (strchr("bckmgtBCKMGT", optarg[0]) == NULL ||
+                           optarg[1] != '\0') {
+                               fprintf(stderr, "Valid units are bckmgt\n");
+                               exit(1);
+                       }
+                       print_unit = tolower(optarg[0]);
                        break;
                case 'n':
                        donothing++;