Add free(1)

Makefile

@@ -18,6 +18,7 @@ SRC = \
 	chvt.c              \
 	df.c                \
 	dmesg.c             \
+	free.c              \
 	halt.c              \
 	insmod.c            \
 	lsmod.c             \

free.c

@@ -0,0 +1,69 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/sysinfo.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: %s [-bkmg]\n", argv0);
+}
+
+static unsigned int mem_unit = 1;
+static unsigned int unit_shift;
+
+static unsigned long long
+scale(unsigned long long v)
+{
+	return (v * mem_unit) >> unit_shift;
+}
+
+int
+main(int argc, char *argv[])
+{
+	struct sysinfo info;
+
+	sysinfo(&info);
+	mem_unit = info.mem_unit ? info.mem_unit : 1;
+
+	ARGBEGIN {
+	case 'b':
+		unit_shift = 0;
+		break;
+	case 'k':
+		unit_shift = 10;
+		break;
+	case 'm':
+		unit_shift = 20;
+		break;
+	case 'g':
+		unit_shift = 30;
+		break;
+	default:
+		usage();
+	} ARGEND;
+
+	printf("     %13s%13s%13s%13s%13s\n",
+	       "total",
+	       "used",
+	       "free",
+	       "shared", "buffers");
+	printf("Mem: ");
+	printf("%13llu%13llu%13llu%13llu%13llu\n",
+	       scale(info.totalram),
+	       scale(info.totalram - info.freeram),
+	       scale(info.freeram),
+	       scale(info.sharedram),
+	       scale(info.bufferram));
+	printf("-/+ buffers/cache:");
+	printf("%13llu%13llu\n",
+	       scale(info.totalram - info.freeram - info.bufferram),
+	       scale(info.freeram + info.bufferram));
+	printf("Swap:");
+	printf("%13llu%13llu%13llu\n",
+	       scale(info.totalswap),
+	       scale(info.totalswap - info.freeswap),
+	       scale(info.freeswap));
+	return 0;
+}