Might as well commit this to have the history. It's not linked in to the

applet list yet (and won't be until it can replace lash, I'm not having five
shells in menuconfig at once), but you can build it with scripts/individual
and mostly this is checked in so I can bloatcheck future versions against it
easily....

This is about as small as a shell can get and still be a shell.

shell/bbsh.c

@@ -0,0 +1,73 @@
+/* vi: set ts=4 :
+ * 
+ * bbsh - busybox shell
+ *
+ * Copyright 2006 Rob Landley <rob@landley.net>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+// Handle embedded NUL bytes in the command line.
+
+#include <busybox.h>
+
+static int handle(char *command)
+{
+	int argc=0;
+	char *argv[10], *start = command;
+
+	// Parse command into argv[]
+	for (;;) {
+		char *end;
+
+		// Skip leading whitespace and detect EOL.
+		while(isspace(*start)) start++;
+		if(!*start || *start=='#') break;
+
+		// Grab next word.  (Add dequote and envvar logic here)
+		end=start;
+		while(*end && !isspace(*end)) end++;
+		argv[argc++]=xstrndup(start,end-start);
+		start=end;
+	}
+	argv[argc]=0;
+
+	if (!argc) return 0;
+	if (argc==2 && !strcmp(argv[0],"cd")) chdir(argv[1]);
+	else if(!strcmp(argv[0],"exit")) exit(argc>1 ? atoi(argv[1]) : 0); 
+	else {
+		int status;
+		pid_t pid=fork();
+		if(!pid) {
+			run_applet_by_name(argv[0],argc,argv);
+			execvp(argv[0],argv);
+			printf("No %s",argv[0]);
+			exit(1);
+		} else waitpid(pid, &status, 0);
+	}
+	while(argc) free(argv[--argc]);
+
+	return 0;
+}
+
+int bbsh_main(int argc, char *argv[])
+{
+	char *command=NULL;
+	FILE *f;
+
+	bb_getopt_ulflags(argc, argv, "c:", &command);
+
+	f = argv[optind] ? xfopen(argv[optind],"r") : NULL;
+	if (command) handle(command);
+	else {
+		unsigned cmdlen=0;
+		for (;;) {
+			if(!f) putchar('$');
+			if(1 > getline(&command,&cmdlen,f ? : stdin)) break;
+			handle(command);
+		}
+		if (ENABLE_FEATURE_CLEAN_UP) free(command);
+	}
+		
+	return 1;
+}