From b34d9590cbc269acb257581b347c825d624576c2 Mon Sep 17 00:00:00 2001
From: Lisa Milne <lisamilne618@gmail.com>
Date: Sat, 25 Nov 2023 20:43:51 +1000
Subject: [PATCH] move shell to /bin/sh (and shell.js)

---
 clite/core.js  | 629 +++++++++++++------------------------------------
 clite/shell.js | 269 +++++++++++++++++++++
 readme.txt     |   3 +
 3 files changed, 440 insertions(+), 461 deletions(-)
 create mode 100644 clite/shell.js

diff --git a/clite/core.js b/clite/core.js
index 4a9dc50..19af49e 100644
--- a/clite/core.js
+++ b/clite/core.js
@@ -34,7 +34,7 @@ var clite = {
 			file:function(name,callback) {
 				if (window.location.protocol == 'file:') { // this is a dirty hack and I hate it, just let me open a file: path!
 					clite.term.setCustom({type:'file',callback:callback});
-					clite.shell.writeLine('open file: '+name);
+					//clite.shell.writeLine('open file: '+name);
 					return;
 				}
 
@@ -79,7 +79,7 @@ var clite = {
 		this.state.isinit = true;
 
 		this.core.execSafeAsync(function() {
-			clite.term.clear(false);
+			clite.term.clear();
 			var vfsapi = null;
 
 			function defaultDevices() {
@@ -196,8 +196,9 @@ var clite = {
 						buffer:[],
 						input:function(str) {
 							if (n.data.content.receive.callback != null) {
+								var fn = n.data.content.receive.callback;
 								clite.core.execSafeAsync(function() {
-									n.data.content.receive.callback(str);
+									fn(str);
 								});
 								n.data.content.receive.callback = null;
 								return;
@@ -212,6 +213,8 @@ var clite = {
 							return true;
 						}
 						n.data.content.receive.callback = cb;
+						clite.term.genForm();
+						clite.term.data.field.focus();
 						return true;
 					},
 					write:clite.term.writeLine
@@ -350,6 +353,10 @@ readme.txt:/usr/clite/readme:0:0:-rw-r--r--`;
 				clite.core.load.script('clite/commands.js',init3);
 			}
 			function init3(data) {
+				clite.core.execSafe(clite.commands.data);
+				clite.core.load.script('clite/shell.js',init4);
+			}
+			function init4(data) {
 				clite.core.execSafe(clite.commands.data);
 				clite.commands = null;
 				clite.log.write('Bringing up the process manager');
@@ -380,22 +387,56 @@ readme.txt:/usr/clite/readme:0:0:-rw-r--r--`;
 					//  read in /usr/share/introduction and write to shell
 					if (window.location.protocol == 'file:') {
 						clite.user.genGuest();
-						clite.shell.writeLine(clite_text);
+						//clite.shell.writeLine(clite_text);
 					}else{
-						var fd = clite.io.open('/usr/share/introduction',function(fd) {
-							clite.user.genGuest();
-						clite.shell.writeLine(clite_text);
-							if (!fd)
-								return;
-							var d = clite.io.readAll(fd);
-							if (d != null)
-								clite.shell.writeLine(d);
-							clite.io.close(fd);
+						//var fd = clite.io.open('/usr/share/introduction',function(fd) {
+							//clite.user.genGuest();
+						//clite.shell.writeLine(clite_text);
+							//if (!fd)
+								//return;
+							//var d = clite.io.readAll(fd);
+							//if (d != null)
+								//clite.shell.writeLine(d);
+							//clite.io.close(fd);
 
-						});
+						//});
 					}
+					// create the login shell
+					// should really have init/getty exec the shell with the env data etc
+					var env = clite.user.getEnv();
+					var io = {
+						stdin:clite.io.open('/dev/tty',false),
+						stdout:clite.io.open('/dev/tty',false),
+						stderr:clite.io.open('/dev/tty',false),
+						exit:null,
+						include:function(name) {
+							switch (name) {
+							case 'stdlib':
+								return clite.lib.api;
+								break;
+							case 'stdio':
+								return clite.io;
+								break;
+							case 'term':
+								return clite.term.api;
+								break;
+							default:
+								return null;
+								break;
+							}
+							return null;
+						},
+						istty:{
+							stdin:true,		// false if stdin (read) is not clite.shell.readLine
+							stdout:true		// false if stdout (write) is not clite.term.writeLine
+						}
+					};
+					clite.lib.fork(env,io,init5);
 				}
 			}
+			function init5(env,io) {
+				clite.lib.exec('/bin/sh',['sh'],env,io);
+			}
 
 			init1();
 
@@ -577,9 +618,6 @@ clite.user = {
 			vfs.mkLink('/usr/home/guest/web','/usr/share/site');
 
 			setLogin(1);
-
-			// should really have init/getty exec the shell with the env data etc
-			clite.shell.init();
 		}
 		clite.user.getEnv = function() {
 			return structuredClone(udata.env);
@@ -900,6 +938,13 @@ clite.io = {
 			var fd = getFileDes(path,true,false);
 			return clite.io.fchmod(fd,mode);
 		}
+		clite.io.isatty = function(fd) {
+			return fd.node.data.istty;
+		}
+		clite.io.fprintf = function(fd,fmt) {
+			// TODO: actually support formatting
+			return clite.io.write(fd,fmt);
+		}
 	},
 	// 0: unknown
 	// 1: text file
@@ -936,7 +981,9 @@ clite.io = {
 	stat:null,
 	fstat:null,
 	chmod:null,
-	fchmod:null
+	fchmod:null,
+	isatty:null,
+	fprintf:null
 };
 
 clite.vfs = {
@@ -1174,54 +1221,35 @@ clite.term = {
 		type:'text',
 		form:null,
 		field:null,
-		handler:null
+		handler:null,
+		prompt:''
 	},
 	events:{
 		keydown:function(e) {
-			return clite.term.events.keypress(e);
-		},
-		keypress:function(e) {
 			if (e.key == 'Tab') {
-				clite.shell.tabfill();
 				clite.term.events.refocus();
 				return false;
 			}
 			return true;
 		},
 		keyup:function(e) {
-			//if (e.key.length > 1 && e.key != 'Spacebar' && clite.term.data.handler != null) {
-				//if (e.key == 'Enter') {
-					//clite.term.data.handler(e.target.value);
-				//}else{
-					//clite.term.data.handler(e.key);
-				//}
-			//}
-			try {
-				if (e.key == 'Down' || e.key == 'ArrowDown') {
-					clite.shell.history.down();
-					return false;
+			if (e.key.length > 1 && e.key != 'Spacebar' && clite.term.data.handler != null) {
+				if (e.key == 'Enter') {
+					clite.term.data.handler(e.target.value);
+				}else{
+					clite.term.data.handler('\1'+e.key);
 				}
-				if (e.key == 'Up' || e.key == 'ArrowUp') {
-					clite.shell.history.up();
-					return false;
-				}
-				if (e.key == 'Tab') {
-					return false;
-				}
-				var t = clite.term.data.field.value;
-				if (e.key != 'Enter') {
-					clite.shell.history.setCurrent(t);
-					return true;
-				}
-				clite.shell.run(t);
-				return false;
-			} catch(err) {return false;}
+			}
+			return false;
 		},
 		refocus:function(e) {
-			try {
-				clite.term.genForm();
-				clite.term.data.field.focus();
-			} catch(err) {}
+			clite.core.execSafeAsync(function() {
+				try{
+					clite.term.data.field.focus()
+				} catch(err) {
+					clite.term.genForm();
+				}
+			});
 		}
 	},
 	tty:{
@@ -1242,10 +1270,8 @@ clite.term = {
 			return clite.term.tty.data.data.onkeypress(e);
 		}
 	},
-	clear:function(form) {
+	clear:function() {
 		document.getElementById('terminal').innerHTML = '';
-		if (form)
-			clite.term.genForm();
 	},
 	preventInput:function() {
 		return;
@@ -1276,11 +1302,11 @@ clite.term = {
 		f.id = 'form';
 		f.innerHTML = '';
 		var l = document.createElement('label');
-		l.innerHTML = clite.shell.prompt.getHTML();
+		l.innerHTML = clite.lib.htmlEncode(clite.term.data.prompt);
 		f.appendChild(l);
 		var i = document.createElement('input');
 		i.type = clite.term.getType();
-		i.value = clite.shell.history.getCurrent();
+		//i.value = clite.shell.history.getCurrent();
 		f.appendChild(i);
 		clite.term.data.form = f;
 		clite.term.data.field = i;
@@ -1288,19 +1314,8 @@ clite.term = {
 		if (!t)
 			return;
 		t.appendChild(f);
-		if (clite.term.tty.data != null) {
-			i.onkeydown = clite.term.tty.keydown;
-			i.onkeypress = clite.term.tty.keypress;
-			i.onkeyup = clite.term.tty.keyup;
-		}else if (clite.shell.reading.is) {
-			i.onkeydown = clite.shell.reading.keydown;
-			i.onkeypress = clite.shell.reading.keypress;
-			i.onkeyup = clite.shell.reading.keyup;
-		}else{
-			i.onkeydown = clite.term.events.keydown;
-			i.onkeypress = clite.term.events.keypress;
-			i.onkeyup = clite.term.events.keyup;
-		}
+		i.onkeydown = clite.term.events.keydown;
+		i.onkeyup = clite.term.events.keyup;
 		i.onfocusout = clite.term.events.refocus;
 		i.onblur = clite.term.events.refocus;
 		if (i.type == 'file') { // this is only needed due to dirty hacks to read in a file: path
@@ -1339,10 +1354,41 @@ clite.term = {
 		return 'text';
 	},
 	api:{
-		clear:function() { // clears the terminal
-			clite.term.clear(false);
+		// clears the terminal
+		clear:function() {
+			clite.term.clear();
 		},
-		opentty:function() { // gets an empty element with key events (allows view/less to display content in a clean element)
+		ttyctrl:function(fn,v) {
+			switch (fn) {
+			case 'iget': // returns the current input string - bypassing tty read
+				try{
+					return clite.term.data.field.value;
+				} catch(err) {
+					return '';
+				}
+				break;
+			case 'iset': // sets the current input string
+				try{
+					if (typeof v !== 'string')
+						v = '';
+					clite.term.data.field.value = v;
+					return true;
+				} catch(err) {
+					return false;
+				}
+				break;
+			case 'prompt': // sets the prompt for input
+				if (typeof v !== 'string')
+					v = '';
+				clite.term.data.prompt = v;
+				return true;
+				break;
+			default:
+				return false;
+			}
+		},
+		// gets an empty element with key events (allows view/less to display content in a clean element)
+		opentty:function() {
 			var tty = {
 				handleKeys:function(cb) {
 					this.data.cb = cb;
@@ -1411,384 +1457,6 @@ clite.term = {
 	}
 };
 
-clite.shell = {
-	reading:{
-		is:false,
-		buff:'',
-		callback:null,
-		keydown:function(e) {
-			if (e.key == 'Tab')
-				return false;
-		},
-		keypress:function(e) {
-			if (e.key == 'Tab') {
-				clite.term.events.refocus();
-				return false;
-			}
-		},
-		keyup:function(e) {
-			if (e.key.length > 1 && e.key != 'Spacebar') {
-				clite.shell.reading.is = false;
-				clite.term.preventInput();
-				if (e.key == 'Enter') {
-					clite.shell.reading.callback(clite.shell.reading.buff);
-				}else{
-					clite.shell.reading.callback(e);
-				}
-				return false;
-			}
-			clite.shell.reading.buff = e.target.value;
-		}
-	},
-	init:function() {
-		clite.shell.env = clite.user.getEnv();
-		clite.shell.prompt.generate();
-		clite.term.events.refocus();
-	},
-	exit:function(pid,v) {
-		if (pid > -1)
-			clite.proc.exit(pid);
-		if (clite.term.tty.data != null)
-			clite.term.api.closetty(clite.term.tty.data);
-		clite.shell.prompt.pop();
-		clite.term.events.refocus();
-	},
-	readLine:function(cb) {
-		clite.shell.reading.is = true;
-		clite.shell.reading.buff = '';
-		clite.shell.reading.callback = cb;
-		clite.term.events.refocus();
-	},
-	writeLine:function(txt) {
-		clite.term.writeLine(txt);
-		clite.term.events.refocus();
-	},
-	resolvePath:function(txt) {
-		var paths = clite.shell.env.PATH.split(':');
-		var path = null;
-		paths.forEach(function(p) {
-			if (path)
-				return;
-			var rp = clite.lib.resolvePath(txt,p);
-			var fd = clite.io.open(rp,false);
-			if (fd) {
-				clite.io.close(fd);
-				path = rp;
-			}
-		});
-		return path;
-	},
-	include:function(name) {
-		switch (name) {
-		case 'stdlib':
-			return clite.lib.api;
-			break;
-		case 'stdio':
-			return clite.io;
-			break;
-		case 'term':
-			return clite.term.api;
-			break;
-		default:
-			return null;
-			break;
-		}
-		return null;
-	},
-	preprocess:function(txt) {
-		var parts = txt.split('$');
-		var pptxt = '';
-		if (parts.length == 1)
-			return txt;
-		parts.forEach(function(p,i) {
-			if (i > 0) {
-				var b = p;
-				var e = '';
-				var pi = b.indexOf(' ');
-				if (pi > 0) {
-					e = b.substring(pi);
-					b = b.substring(0,pi);
-				}
-				if (b[0] == '{') {
-					var pi = b.indexOf('}');
-					b = b.substring(1,pi);
-				}
-				if (typeof clite.shell.env[b] === 'string') {
-					b = clite.shell.env[b];
-				}else{
-					b = '';
-				}
-				pptxt = b+e;
-				return;
-			}
-			pptxt += p;
-		});
-		txt = pptxt;
-		parts = txt.split('`');
-		pptxt = '';
-		if (parts.length == 1)
-			return txt;
-		parts.forEach(function(p,i) {
-			if (i > 0) {
-				var b = p;
-				var e = '';
-				var pi = b.indexOf('`');
-				if (pi > 0) {
-					e = b.substring(pi);
-					b = b.substring(0,pi);
-				}
-				// TODO: replace b with the output of the command in b (command substitution)
-				pptxt = b+e;
-				return;
-			}
-			pptxt += p;
-		});
-		return pptxt;
-	},
-	run:function(txt) {
-		if (txt.length < 1) {
-			clite.shell.writeLine(clite.shell.prompt.get());
-			return;
-		}
-		clite.shell.history.add(txt);
-		clite.shell.history.resetCurrent();
-		clite.shell.writeLine(clite.shell.prompt.get()+txt);
-		clite.shell.prompt.push('');
-		clite.term.preventInput();
-		// split command line into arguments
-		var args = clite.lib.strToArgs(txt);
-		args.forEach(function(val,i) {
-			args[i] = clite.shell.preprocess(val);
-		});
-		// prepare io (stdin,stdout,stderr)
-		// TODO: check for io redirects and piping, then setup stdio accordingly
-		var io = {
-			read:clite.shell.readLine,	// stdin
-			write:clite.term.writeLine,	// stdout
-			error:clite.term.writeLine,	// stderr
-			exit:clite.shell.exit,		// equivalent to C's exit(), needed by asynchronous programs
-			include:clite.shell.include,	// include libraries, allows them to be used in a program
-			istty:{
-				stdin:true,		// false if stdin (read) is not clite.shell.readLine
-				stdout:true		// false if stdout (write) is not clite.term.writeLine
-			}
-		};
-		// check for a macro
-		// then either run the macro or expand the program to be executed via PATH
-		if (typeof clite.shell.macro[args[0]] != 'undefined') {
-			var r = clite.shell.macro[args[0]](args,io);
-			clite.shell.exit(r);
-			return;
-		}
-
-		var path = clite.shell.resolvePath(args[0]);
-		if (!path) {
-			clite.term.writeLine('Shell: unknown command: '+args[0]);
-			clite.shell.exit(-1,-1);
-			return;
-		}
-
-		function execFunc(env,io) {
-			var r = clite.lib.exec(path,args,env,io);
-			if (r == 0)
-				return;
-
-			if (r == -1) {
-				clite.term.writeLine('Shell: unknown command: '+args[0]);
-				clite.shell.exit(-1,-2);
-				return;
-			}
-
-			if (r == -2) {
-				clite.term.writeLine('Shell: error in command:'+args[0]);
-				clite.shell.exit(-1,-3);
-			}
-		}
-		if (!clite.lib.fork(clite.shell.env,io,execFunc)) {
-			clite.term.writeLine('Shell: internal error');
-			clite.shell.exit(-1,-1);
-		}
-	},
-	tabfill:function() {
-		var c = clite.shell.history.getCurrent();
-		var parts = clite.lib.strToArgs(c);
-		var ai = parts.length-1;
-		if (ai < 0)
-			return;
-		var a = parts[ai];
-		var add = '';
-		if (ai == 0) {
-			// test for shell macros/builtins
-			Object.keys(clite.shell.macro).forEach(function(key) {
-				if (add == '' && key.substring(0,a.length) == a) {
-					add = key.substring(a.length);
-				}
-			});
-			if (add == '') {
-				// test for commands
-				var pparts = clite.shell.env.PATH.split(':');
-				pparts.forEach(function(pp) {
-					if (add != '')
-						return;
-					var fd = clite.io.open('/bin');
-					var f;
-					while (add == '' && (f = clite.io.read(fd)) != null) {
-						if (f.name.substring(0,a.length) == a) {
-							add = f.name.substring(a.length)+' ';
-						}
-					}
-					clite.io.close(fd);
-				});
-			}
-		}else{
-			// TODO: path fill
-		}
-		if (add == '')
-			return;
-		clite.shell.history.setCurrent(c+add);
-	},
-	env:{},
-	macro:{
-		clear:function(args,io) {
-			clite.term.clear();
-		},
-		cd:function(args,io) {
-			var dir = clite.shell.env.HOME;
-			if (args.length > 1) {
-				dir = clite.lib.resolvePath(args[1]);
-			}
-			var fd = clite.io.open(dir,false);
-			if (!fd) {
-				io.error('invalid directory: '+dir);
-				return;
-			}
-			if (!fd.node.data.isdir) {
-				io.error('invalid directory: '+dir);
-				return;
-			}
-			clite.io.close(fd);
-			clite.shell.env.PWD = dir;
-			clite.shell.prompt.generate();
-		},
-		pwd:function(args,io) {
-			io.write(clite.shell.env.PWD);
-		},
-		echo:function(args,io) {
-			args.shift();
-			var txt = args.join(' ');
-			io.write(txt);
-		},
-		which:function(args,io) {
-			if (args.length <2)
-				return;
-			if (typeof clite.shell.macro[args[1]] != 'undefined') {
-				return;
-			}else{
-				var path = clite.shell.resolvePath(args[1]);
-				if (!path)
-					return;
-				io.write(args[1]+' is '+path);
-			}
-		},
-		type:function(args,io) {
-			if (args.length <2)
-				return;
-			if (typeof clite.shell.macro[args[1]] != 'undefined') {
-				io.write(args[1]+' is a shell builtin');
-			}else{
-				var path = clite.shell.resolvePath(args[1]);
-				if (!path)
-					return;
-				io.write(args[1]+' is '+path);
-			}
-		},
-		whoami:function(args,io) {
-			io.write(clite.shell.env.USER);
-		},
-		alias:function(args,io) {
-			io.write('unimplemented');
-		},
-		export:function(args,io) {
-			if (args.length == 1) {
-				Object.keys(clite.shell.env).forEach(function(key) {
-					io.write(key+'='+clite.shell.env[key]);
-				});
-				return;
-			}
-			var parts = args[1].split('=');
-			if (parts.length != 2)
-				return;
-			clite.shell.env[parts[0]] = parts[1];
-		}
-	},
-	prompt:{
-		list:[],
-		data:'# ',
-		set:function(txt) {
-			clite.shell.prompt.list = [];
-			clite.shell.prompt.data = txt;
-		},
-		push:function(txt) {
-			clite.shell.prompt.list.push(clite.shell.prompt.data);
-			clite.shell.prompt.data = txt;
-		},
-		pop:function() {
-			if (clite.shell.prompt.list.length > 0)
-				clite.shell.prompt.data = clite.shell.prompt.list.pop();
-		},
-		generate:function() {
-			var p = clite.shell.env.USER+':'+clite.shell.env.PWD;
-			if (clite.user.getUID() == 0) {
-				p += '# ';
-			}else{
-				p += '$ ';
-			}
-			clite.shell.prompt.set(p);
-		},
-		get:function() {
-			return clite.shell.prompt.data;
-		},
-		getHTML:function() {
-			return clite.lib.htmlEncode(clite.shell.prompt.data);
-		}
-	},
-	history:{
-		data:[],
-		current:'',
-		index:0,
-		add:function(txt) {
-			if (txt.length < 1)
-				return;
-			clite.shell.history.data.push(txt);
-			clite.shell.history.index = clite.shell.history.data.length;
-		},
-		up:function() {
-			if (clite.shell.history.index == 0)
-				return;
-			clite.shell.history.index--;
-			clite.term.events.refocus();
-		},
-		down:function() {
-			if (clite.shell.history.index == clite.shell.history.data.length)
-				return;
-			clite.shell.history.index++;
-			clite.term.events.refocus();
-		},
-		setCurrent:function(txt) {
-			clite.shell.history.current = txt;
-		},
-		getCurrent:function() {
-			if (clite.shell.history.index == clite.shell.history.data.length)
-				return clite.shell.history.current;
-			return clite.shell.history.data[clite.shell.history.index];
-		},
-		resetCurrent:function() {
-			clite.shell.history.current = '';
-			clite.shell.history.index = clite.shell.history.data.length;
-		}
-	}
-};
-
 clite.lib = {
 	// makes text html safe
 	htmlEncode:function(txt) {
@@ -1812,14 +1480,16 @@ clite.lib = {
 	resolvePath:function(txt,base) {
 		if (txt == '/')
 			return txt;
-		if (txt[0] == '~')
-			txt = clite.shell.env.HOME+txt.substring(1);
+		var env = clite.user.getEnv();
+		if (txt[0] == '~') {
+			txt = env.HOME+txt.substring(1);
+		}
 		var path = txt;
 		if (txt[0] != '/') {
 			if (typeof base != 'string')
-				base = clite.shell.env.PWD;
+				base = env.PWD;
 			if (base[0] != '/')
-				base = clite.shell.env.PWD+'/'+base;
+				base = env.PWD+'/'+base;
 			path = base+'/'+txt;
 		}
 		var parts = path.split('/');
@@ -1974,16 +1644,39 @@ clite.lib = {
 		var pid = clite.proc.add(call);
 		if (!pid)
 			return 0;
-		io.exit = function(v) {
-			clite.shell.exit(pid,v);
+		var nio = Object.create(io);
+		nio.exit = function(v) {
+			clite.lib.exit(pid,v);
+		}
+		nio.include = function(name) {
+			switch (name) {
+			case 'stdlib':
+				return Object.create(clite.lib.api);
+				break;
+			case 'stdio':
+				var stdio = Object.create(clite.io);
+				stdio.printf = function(fmt) {
+					// TODO: pass arguments through
+					return stdio.fprintf(nio.stdout,fmt);
+				}
+				return stdio;
+				break;
+			case 'term':
+				return Object.create(clite.term.api);
+				break;
+			default:
+				return null;
+				break;
+			}
+			return null;
 		}
 		clite.core.execSafeAsync(function() {
-			call(structuredClone(env),io);
+			call(structuredClone(env),nio);
 		});
 		return pid;
 	},
 	exec:function(path,args,env,io) {
-		var fd = clite.io.open(path);
+		var fd = clite.io.open(path,false);
 		if (!fd)
 			return -1;
 
@@ -2000,6 +1693,18 @@ clite.lib = {
 			return -2;
 		}
 		return 0;
+	},
+	exit:function(pid,v) {
+		if (pid > -1)
+			clite.proc.exit(pid);
+		if (clite.term.tty.data != null)
+			clite.term.api.closetty(clite.term.tty.data);
+	},
+	getuid:function() {
+		return clite.user.getUID();
+	},
+	getgid:function() {
+		return clite.user.getGID();
 	}
 }
 clite.lib.api = { // this is passed to programs via include('stdlib')
@@ -2009,5 +1714,7 @@ clite.lib.api = { // this is passed to programs via include('stdlib')
 	strToArgs:clite.lib.strToArgs,
 	uname:clite.lib.uname,
 	fork:clite.lib.fork,
-	exec:clite.lib.exec
+	exec:clite.lib.exec,
+	getuid:clite.lib.getuid,
+	getgid:clite.lib.getgid
 };
diff --git a/clite/shell.js b/clite/shell.js
new file mode 100644
index 0000000..8ac7a72
--- /dev/null
+++ b/clite/shell.js
@@ -0,0 +1,269 @@
+clite.commands.data = function() {
+// insert commands below this line
+
+clite.commands.load('sh',function(args,env,io) {
+	var stdio = io.include('stdio');
+	var stdlib = io.include('stdlib');
+	var term = io.include('term');
+	var prompt = '$ ';
+	var macro = {
+		clear:function(args,io) {
+			term.clear();
+		},
+		cd:function(args,io) {
+			var dir = env.HOME;
+			if (args.length > 1) {
+				dir = stdlib.resolvePath(args[1]);
+			}
+			var fd = stdio.open(dir,false);
+			if (!fd) {
+				stdio.write(io.stderr,'invalid directory: '+dir);
+				return;
+			}
+			if (!fd.node.data.isdir) {
+				stdio.write(io.stderr,'invalid directory: '+dir);
+				return;
+			}
+			stdio.close(fd);
+			env.PWD = dir;
+		},
+		pwd:function(args,io) {
+			stdio.write(io.stdout,env.PWD);
+		},
+		echo:function(args,io) {
+			args.shift();
+			var txt = args.join(' ');
+			stdio.write(io.stdout,txt);
+		},
+		which:function(args,io) {
+			if (args.length <2)
+				return;
+			if (typeof macro[args[1]] != 'undefined') {
+				return;
+			}else{
+				var path = resolvePATH(args[1]);
+				if (!path)
+					return;
+				stdio.write(io.stdout,args[1]+' is '+path);
+			}
+		},
+		type:function(args,io) {
+			if (args.length <2)
+				return;
+			if (typeof macro[args[1]] != 'undefined') {
+				stdio.write(io.stdout,args[1]+' is a shell builtin');
+			}else{
+				var path = resolvePATH(args[1]);
+				if (!path)
+					return;
+				stdio.write(io.stdout,args[1]+' is '+path);
+			}
+		},
+		whoami:function(args,io) {
+			stdio.write(io.stdout,env.USER);
+		},
+		alias:function(args,io) {
+			stdio.write(io.stdout,'unimplemented');
+		},
+		export:function(args,io) {
+			if (args.length == 1) {
+				Object.keys(env).forEach(function(key) {
+					stdio.write(io.stdout,key+'='+env[key]);
+				});
+				return;
+			}
+			var parts = args[1].split('=');
+			if (parts.length != 2)
+				return;
+			env[parts[0]] = parts[1];
+		}
+	};
+
+	function resolvePATH(txt) {
+		if (typeof env.PATH === 'undefined')
+			env.PATH = '/bin';
+		var paths = env.PATH.split(':');
+		var path = null;
+		paths.forEach(function(p) {
+			if (path)
+				return;
+			var rp = stdlib.resolvePath(txt,p);
+			var fd = stdio.open(rp,false);
+			if (fd) {
+				stdio.close(fd);
+				path = rp;
+			}
+		});
+		return path;
+	}
+
+	function preprocess(txt) {
+		var parts = txt.split('$');
+		var pptxt = '';
+		if (parts.length == 1)
+			return txt;
+		parts.forEach(function(p,i) {
+			if (i > 0) {
+				var b = p;
+				var e = '';
+				if (b[0] == '{') {
+					var pi = b.indexOf('}');
+					e = b.substring(pi+1);
+					b = b.substring(1,pi);
+				}else{
+					var pi = b.indexOf(' ');
+					if (pi > 0) {
+						e = b.substring(pi);
+						b = b.substring(0,pi);
+					}
+				}
+				if (typeof env[b] === 'string') {
+					b = env[b];
+				}else{
+					b = '';
+				}
+				pptxt += b+e;
+				return;
+			}
+			pptxt += p;
+		});
+		txt = pptxt;
+		parts = txt.split('`');
+		pptxt = '';
+		if (parts.length == 1)
+			return txt;
+		parts.forEach(function(p,i) {
+			if (i > 0) {
+				var b = p;
+				var e = '';
+				var pi = b.indexOf('`');
+				if (pi > 0) {
+					e = b.substring(pi);
+					b = b.substring(0,pi);
+				}
+				// TODO: replace b with the output of the command in b (command substitution)
+				pptxt = b+e;
+				return;
+			}
+			pptxt += p;
+		});
+		return pptxt;
+	}
+
+	function run(txt) {
+		if (txt.length < 1) {
+			stdio.write(io.stdout,prompt);
+			inputRead();
+			return;
+		}
+		//clite.shell.history.add(txt);
+		//clite.shell.history.resetCurrent();
+		stdio.write(io.stdout,prompt+txt);
+		// clear the tty prompt
+		term.ttyctrl('prompt','');
+		// split command line into arguments
+		var args = stdlib.strToArgs(txt);
+		args.forEach(function(val,i) {
+			args[i] = preprocess(val);
+		});
+		// prepare io (stdin,stdout,stderr)
+		// TODO: check for io redirects and piping, then setup stdio accordingly
+		var fio = {
+			stdin:io.stdin,
+			stdout:io.stdout,
+			stderr:io.stderr,
+			exit:null,		// filled in by fork()
+			include:null,		// filled in by fork()
+		};
+		// check for a macro
+		// then either run the macro or expand the program to be executed via PATH
+		if (typeof macro[args[0]] != 'undefined') {
+			var r = macro[args[0]](args,fio);
+			inputRead();
+			return;
+		}
+
+		var path = resolvePATH(args[0]);
+		if (!path) {
+			stdio.write(io.stderr,'Shell: unknown command: '+args[0]);
+			inputRead();
+			return;
+		}
+
+		function execFunc(env,io) {
+			var r = stdlib.exec(path,args,env,io);
+			if (r > 0)
+				return;
+
+			if (r == -1)
+				stdlib.write(io.stderr,'Shell: unknown command: '+args[0]);
+
+			if (r == -2)
+				stdio.write(io.stderr,'Shell: error in command:'+args[0]);
+			inputRead();
+		}
+		if (!stdlib.fork(env,fio,execFunc)) {
+			stdio.write(io.stderr,'Shell: internal error');
+			inputRead();
+		}
+	}
+
+	function inputControl(key) {
+			//try {
+				//if (e.key == 'Down' || e.key == 'ArrowDown') {
+					//clite.shell.history.down();
+					//return false;
+				//}
+				//if (e.key == 'Up' || e.key == 'ArrowUp') {
+					//clite.shell.history.up();
+					//return false;
+				//}
+				//if (e.key == 'Tab') {
+					//return false;
+				//}
+				//var t = clite.term.data.field.value;
+				//if (e.key != 'Enter') {
+					//clite.shell.history.setCurrent(t);
+					//return true;
+				//}
+				//clite.shell.run(t);
+				//return false;
+			//} catch(err) {return false;}
+	}
+	function input(str) {
+		if (str[0] == '\1') {
+			inputControl(str.substring(1));
+			inputRead();
+			return;
+		}
+
+		run(str);
+	}
+	function inputRead() {
+		// generate the prompt
+		var p = env.PS1;
+		if (typeof p === 'undefined')
+			p = '${USER}:${PWD}'
+
+		prompt = preprocess(p);
+		if (stdlib.getuid() == 0) {
+			prompt += '# ';
+		}else{
+			prompt += '$ ';
+		}
+		// set the prompt
+		term.ttyctrl('prompt',prompt);
+		// then read from stdin
+		stdio.read(io.stdin,input);
+	}
+
+	// TODO: this check will exec future shell scripts
+	if (!stdio.isatty(io.stdin))
+		return 0;
+
+	inputRead();
+
+	return null;
+});
+
+}
diff --git a/readme.txt b/readme.txt
index 24d2abf..34c5d5a 100644
--- a/readme.txt
+++ b/readme.txt
@@ -356,6 +356,9 @@ stdio: io.include('stdio')
 	The user has all permissions, the group has read and execute
 	 permissions, others have only read permissions.
 
+ isattty(fd)
+	returns true if fd refers to a tty.
+
 term: io.include('term')
  Provides access to raw terminal and tty functions.