Small comm implementatin from Rob Sullivan. Needed to build perl.

AUTHORS

@@ -128,6 +128,9 @@ Pavel Roskin <proski@gnu.org>
 Gyepi Sam <gyepi@praxis-sw.com>
     Remote logging feature for syslogd
 
+Rob Sullivan <cogito.ergo.cogito@gmail.com>
+    comm
+
 Linus Torvalds <torvalds@transmeta.com>
     mkswap, fsck.minix, mkfs.minix
 

coreutils/Config.in

@@ -59,6 +59,13 @@ config CONFIG_CMP
 	  cmp is used to compare two files and returns the result
 	  to standard output.
 
+config CONFIG_COMM
+	bool "comm"
+	default n
+	help
+	  comm is used to compare two files line by line and return
+	  a three-column output.
+
 config CONFIG_CP
 	bool "cp"
 	default n

coreutils/comm.c

@@ -0,0 +1,155 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Mini comm implementation for busybox
+ *
+ * Copyright (C) 2005 by Robert Sullivan <cogito.ergo.cogito@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307 USA
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "busybox.h"
+
+#define COMM_OPT_1 0x01
+#define COMM_OPT_2 0x02
+#define COMM_OPT_3 0x04
+
+/* These three variables control behaviour if non-zero */
+
+static int only_file_1;
+static int only_file_2;
+static int both;
+
+/* writeline outputs the input given, appropriately aligned according to class */
+static void writeline (char *line, int class) {
+	switch (class) {
+		case 1: if (!only_file_1)
+				return;
+			break;
+		case 2: if (!only_file_2)
+				return;
+			if (only_file_1)
+				putchar('\t');
+			break;
+		case 3: if (!both)
+				return;
+			if (only_file_1)
+				putchar('\t');
+			if (only_file_2)
+				putchar('\t');
+			break;
+	}
+	fputs(line, stdout);	
+}
+
+/* This is the real core of the program - lines are compared here */
+static int cmp_files(char **infiles) {
+
+	char thisline[2][100];
+	FILE *streams[2];
+	int i = 0;
+	
+	for (i = 0; i < 2; i++) {
+		streams[i] = (strcmp(infiles[i], "=") == 0 ? stdin : fopen(infiles[i], "r"));
+		fgets(thisline[i], 100, streams[i]);
+	}
+
+	while (thisline[0] || thisline[1]) {
+		
+		int order = 0;
+		int tl0_len = strlen(thisline[0]);
+		int tl1_len = strlen(thisline[1]);
+		if (!thisline[0])
+			order = 1;
+		else if (!thisline[1]) 
+			order = -1;
+		else {
+			order = memcmp(thisline[0], thisline[1], tl0_len < tl1_len ? tl0_len : tl1_len);
+			if (!order)
+				order = tl0_len < tl1_len ? -1 : tl0_len != tl1_len;
+		}
+		
+		if ((order == 0) && (!feof(streams[0])) && (!feof(streams[1])))
+			writeline(thisline[1], 3);
+		else if ((order > 0) && (!feof(streams[1])))
+			writeline(thisline[1], 2);
+		else if ((order < 0) && (!feof(streams[0])))
+			writeline(thisline[0], 1);
+		
+		if (feof(streams[0]) && feof(streams[1])) {
+			fclose(streams[0]);
+			fclose(streams[1]);
+			break;
+		}
+		else if (feof(streams[0])) {
+		
+			while (!feof(streams[1])) {
+				if (order < 0)
+					writeline(thisline[1], 2);
+				fgets(thisline[1], 100, streams[1]);
+			}
+			fclose(streams[0]);
+			fclose(streams[1]);
+			break;
+		}
+		else if (feof(streams[1])) {
+
+			while (!feof(streams[0])) {
+				if (order > 0)
+					writeline(thisline[0], 1);
+				fgets(thisline[0], 100, streams[0]);
+			}
+			fclose(streams[0]);
+			fclose(streams[1]);
+			break;
+		}
+		else {
+			if (order >= 0)
+				fgets(thisline[1], 100, streams[1]);
+			if (order <= 0)
+				fgets(thisline[0], 100, streams[0]);
+		}
+	}
+
+	return 0;
+}
+
+int comm_main (int argc, char **argv) {
+	
+	unsigned long opt;
+	only_file_1 = 1;
+	only_file_2 = 1;
+	both = 1;
+	
+	opt = bb_getopt_ulflags(argc, argv, "123");
+	
+        if ((opt & 0x80000000UL) || (optind == argc)) {
+                bb_show_usage();
+        }
+	
+	if (opt & COMM_OPT_1)
+		only_file_1 = 0;
+	if (opt & COMM_OPT_2)
+		only_file_2 = 0;
+	if (opt & COMM_OPT_3)
+		both = 0;
+
+	exit(cmp_files(argv + optind) == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
+}

include/applets.h

@@ -113,6 +113,9 @@
 #ifdef CONFIG_CMP
 	APPLET(cmp, cmp_main, _BB_DIR_USR_BIN, _BB_SUID_NEVER)
 #endif
+#ifdef CONFIG_COMM
+	APPLET(comm, comm_main, _BB_DIR_USR_BIN, _BB_SUID_NEVER)
+#endif
 #ifdef CONFIG_CP
 	APPLET(cp, cp_main, _BB_DIR_BIN, _BB_SUID_NEVER)
 #endif

include/usage.h

@@ -222,6 +222,15 @@
 	"\t\t  for all differing bytes\n" \
 	"\t-s\tquiet mode - do not print"
 
+#define comm_trivial_usage \
+	"[-123] FILE1 FILE2"
+#define comm_full_usage \
+	"Compare files. Compares FILE1 to FILE2, or to stdin if - is specified.\n\n" \
+	"Options:\n" \
+	"\t-1\tSuppress lines unique to FILE1\n" \
+	"\t-2\tSuppress lines unique to FILE2\n" \
+	"\t-3\tSuppress lines common to both files"
+
 #define cp_trivial_usage \
 	"[OPTION]... SOURCE DEST"
 #define cp_full_usage \