libc: option parsing (hasflag/optval); wc -l/-w/-c, head -n N

- hasflag(argv,argc,f): single-char flag present (-f or within -abc)
- optval(argv,argc,opt): value for -opt (-n 5 or -n5)
- wc supports -l/-w/-c (default all); head supports -n N (and bare N)

1 files changed, 7 insertions, 6 deletions

diff --git a/c/head.c b/c/head.c
index 9363b1c..952d4c5 100644
--- a/c/head.c
+++ b/c/head.c
@@ -1,12 +1,13 @@
 #include "gbos.h"
-/* head [n]: print the first n lines of stdin (default 10). Drains the rest to
-   EOF so the shell sees a clean end of input. */
+/* head [-n N] [N]: print the first N lines of stdin (default 10). */
 void main(void) {
-    char *a = getargs();
-    unsigned char n = 10;
-    unsigned char lines = 0;
+    char *argv[8];
+    unsigned char argc = argv_parse(argv, 8);
+    char *nv = optval(argv, argc, 'n');
+    unsigned char n = 10, lines = 0;
     char c;
-    if (*a) n = atou(a);
+    if (nv) n = atou(nv);
+    else if (argc > 0 && argv[0][0] >= '0' && argv[0][0] <= '9') n = atou(argv[0]);
     for (;;) {
         c = readc();
         if (c == EOF) break;