new utilities.
the .C files compile but are renamed to avoid building automatically.
diff --git a/src/cmd/cmp.c b/src/cmd/cmp.c
new file mode 100644
index 0000000..4f69e18
--- /dev/null
+++ b/src/cmd/cmp.c
@@ -0,0 +1,112 @@
+#include <u.h>
+#include <libc.h>
+
+#define BUF 65536
+
+int sflag = 0;
+int lflag = 0;
+int Lflag = 0;
+
+static void usage(void);
+
+void
+main(int argc, char *argv[])
+{
+ int n, i;
+ uchar *p, *q;
+ uchar buf1[BUF], buf2[BUF];
+ int f1, f2;
+ vlong nc = 1, o, l = 1;
+ char *name1, *name2;
+ uchar *b1s, *b1e, *b2s, *b2e;
+
+ ARGBEGIN{
+ case 's': sflag = 1; break;
+ case 'l': lflag = 1; break;
+ case 'L': Lflag = 1; break;
+ default: usage();
+ }ARGEND
+ if(argc < 2)
+ usage();
+ if((f1 = open(name1 = *argv++, OREAD)) == -1){
+ if(!sflag) perror(name1);
+ exits("open");
+ }
+ if((f2 = open(name2 = *argv++, OREAD)) == -1){
+ if(!sflag) perror(name2);
+ exits("open");
+ }
+ if(*argv){
+ o = strtoll(*argv++, 0, 0);
+ if(seek(f1, o, 0) < 0){
+ if(!sflag) perror("cmp: seek by offset1");
+ exits("seek 1");
+ }
+ }
+ if(*argv){
+ o = strtoll(*argv++, 0, 0);
+ if(seek(f2, o, 0) < 0){
+ if(!sflag) perror("cmp: seek by offset2");
+ exits("seek 2");
+ }
+ }
+ if(*argv)
+ usage();
+ b1s = b1e = buf1;
+ b2s = b2e = buf2;
+ for(;;){
+ if(b1s >= b1e){
+ if(b1s >= &buf1[BUF])
+ b1s = buf1;
+ n = read(f1, b1s, &buf1[BUF] - b1s);
+ b1e = b1s + n;
+ }
+ if(b2s >= b2e){
+ if(b2s >= &buf2[BUF])
+ b2s = buf2;
+ n = read(f2, b2s, &buf2[BUF] - b2s);
+ b2e = b2s + n;
+ }
+ n = b2e - b2s;
+ if(n > b1e - b1s)
+ n = b1e - b1s;
+ if(n <= 0)
+ break;
+ if(memcmp((void *)b1s, (void *)b2s, n) != 0){
+ if(sflag)
+ exits("differ");
+ for(p = b1s, q = b2s, i = 0; i < n; p++, q++, i++) {
+ if(*p == '\n')
+ l++;
+ if(*p != *q){
+ if(!lflag){
+ print("%s %s differ: char %lld",
+ name1, name2, nc+i);
+ print(Lflag?" line %lld\n":"\n", l);
+ exits("differ");
+ }
+ print("%6lld 0x%.2x 0x%.2x\n", nc+i, *p, *q);
+ }
+ }
+ }
+ if(Lflag)
+ for(p = b1s; p < b1e;)
+ if(*p++ == '\n')
+ l++;
+ nc += n;
+ b1s += n;
+ b2s += n;
+ }
+ if(b1e - b1s == b2e - b2s)
+ exits((char *)0);
+ if(!sflag)
+ print("EOF on %s\n", (b1e - b1s > b2e - b2s)? name2 : name1);
+ exits("EOF");
+}
+
+static void
+usage(void)
+{
+ print("Usage: cmp [-lsL] file1 file2 [offset1 [offset2] ]\n");
+ exits("usage");
+}
