diff --git a/lib/commands/stack/ssh.js b/lib/commands/stack/ssh.js
index b3e7f97..6938b09 100644
--- a/lib/commands/stack/ssh.js
+++ b/lib/commands/stack/ssh.js
@@ -10,7 +10,7 @@ const IDLE_INTERVAL = 30_000;
 
 const INITIAL_SIZE_WAIT = 700;
 
-function connect( data ) {
+function connect( data, porcelain = false ) {
 	let idleTimer;
 	let lastWasNewline = true;
 	let startedSshControl = false;
@@ -85,7 +85,6 @@ function connect( data ) {
 
 						msg += char;
 					}
-
 					session.write( msg );
 				} );
 			}, 1000 );
@@ -109,11 +108,28 @@ function connect( data ) {
 		}
 
 		const message = reason ? `${ reason }. Disconnected.` : 'Disconnected.';
-		process.stderr.write( message );
+		if ( ! porcelain ) {
+			process.stdout.write( message );
+		}
 		session.close();
 		process.exit();
 	} );
+
+	let firstOutput = true;
 	session.on( 'output', ( data ) => {
+
+		// If this is the first output chunk and we're in porcelain mode, strip the initial 2 lines
+		// this contain somethign like:
+		//     exec sudo sandbox-exec 'clear; $command'
+		//     sh-4.2$ exec sudo sandbox-exec 'clear; $command'
+		if ( porcelain && firstOutput ) {
+			data = data.split( '\n' ).slice(2).join('\n').trim();
+		}
+		firstOutput = false;
+		// Strip the ANSI escape codes if we're in porcelain mode.
+		if ( porcelain ) {
+			data = data.replace(/[\u001b\u009b][[()#;?]*(?:[0-9]{1,4}(?:;[0-9]{0,4})*)?[0-9A-ORZcf-nqry=><]/g, '');
+		}
 		process.stdout.write( data );
 	} );
 }
@@ -123,39 +139,62 @@ const handler = function ( argv ) {
 
 	getStack( argv ).then( stack => {
 		const v = new Vantage( config );
-
 		const status = new ora( `Starting session on ${stack}` );
-		status.start();
+
+		if ( ! argv.command ) {
+			status.start();
+		}
 
 		const url = `stack/applications/${stack}/cli/sessions`;
-		v.fetch( url, { method: 'POST' } ).then( resp => {
+		const args = {
+			motd: ! argv.command,
+		};
+
+		if ( argv.command ) {
+			// Set the SHELL_PIPE=1 env var when running the command if the current process is piped.
+			args.command = `${ process.stdout.isTTY ? '' : 'SHELL_PIPE=1 ' }${ argv.command }`;
+		}
+
+		const options = {
+			method: 'POST',
+			body: JSON.stringify( args ),
+			headers: {
+				'Content-Type': 'application/json',
+			},
+		};
+
+		v.fetch( url, options ).then( resp => {
 			// hm-stack currently returns a 500 for invalid stacks, so we have to
 			// assume any failure is a 404: https://github.com/humanmade/hm-stack/issues/367
 			if ( ! resp.ok ) {
 				status.fail( `Invalid stack ${stack}` );
 				return;
 			}
-
-			return resp.json().then( data => {
+			return resp.text().then( text => {
+				const data = JSON.parse( text );
 				status.stop();
-				connect( data );
-			});
+				connect( data, !! argv.command );
+			} );
 		}).catch( e => {
-			status.fail( `Could not fetch details for ${stack}` );
+			status.fail( `Could create session ${stack} (${e.message})` );
 			throw e;
 		});
 	} );
 };
 
 module.exports = {
-    command: 'ssh [stack]',
-    description: 'SSH into a stack.',
-    builder: subcommand => {
-        subcommand.option( 'app-server', {
-            description: 'Use an app server instead of the sandbox.',
-            default: false,
-            type: 'boolean',
-        } );
-    },
+	command: 'ssh [stack]',
+	description: 'SSH into a stack.',
+	builder: subcommand => {
+		subcommand.option( 'app-server', {
+			description: 'Use an app server instead of the sandbox.',
+			default: false,
+			type: 'boolean',
+		} );
+		subcommand.option( 'command', {
+			description: 'Run a given command and exit.',
+			type: 'string',
+		} );
+	},
 	handler,
 };