run README build and deploy commands through bash shell (fix #21)

README.md

@@ -33,24 +33,23 @@ If you'd like, make sure to include the following comment code tag in your READM
 build and deploy your sample:
 
 ```text
-[//]: # ({sst-run-unix})
+[//]: # ({sst-run-bash})
 ```
 
 For example:
 ````text
-[//]: # ({sst-run-unix})
+[//]: # ({sst-run-bash})
 ```
 gcloud builds submit --tag=gcr.io/${GOOGLE_CLOUD_PROJECT}/run-mysql
 ```
 ````
 
 When parsing the README for custom build and deploy commands, the serverless sample tester will include any commands
-inside a code fence that is immediately preceded by a line containing `{sst-run-unix}`. You can use Markdown syntax
-(e.g. `[//]: # ({sst-run-unix})`) to include this line without making it visible when rendered.
+inside a code fence that is immediately preceded by a line containing `{sst-run-bash}`. You can use Markdown syntax
+(e.g. `[//]: # ({sst-run-bash})`) to include this line without making it visible when rendered.
 
-The parsed commands will not be run through a shell, meaning that the program will not perform any expansions,
-pipelines, redirections or any other functions that shells are responsible for. This also means that popular shell
-builtin commands like `cd`, `export`, and `echo` will not be available or may not work as expected.  
+The parsed commands will be run through the Bash shell, but each command will be run through a separate instance
+of the shell, meaning that commands such as `cd` or `export` may not work as expected.  
 
 However, any environment variables referenced in the form of `$var` or `${var}` will expanded. In addition, bash-style
 multiline commands (i.e. non-quoted backslashes at the end of a line that indicate a line continuation) will also be 

internal/lifecycle/readme.go

@@ -27,7 +27,7 @@ import (
 const (
 	// The tag that should appear immediately before code blocks in a README to indicate that the enclosed commands
 	// are to be used by this program for building and deploying the sample.
-	codeTag = "{sst-run-unix}"
+	codeTag = "{sst-run-bash}"
 
 	// A non-quoted backslash in bash at the end of a line indicates a line continuation from the current line to the
 	// next line.
@@ -49,9 +49,9 @@ var (
 // terminal commands inside of a Markdown code block.
 type codeBlock []string
 
-// toCommands extracts the terminal commands contained within the current codeBlock. It handles the expansion of
-// environment variables and line continuations. It also detects Cloud Run service names Google Container Registry
-// container image URLs and replaces them with the ones provided.
+// toCommands extracts the terminal commands contained within the current codeBlock and creates `exec.Cmd`s for them
+// that pass them through the Bash shell. It also detects Cloud Run service names Google Container Registry container
+// image URLs and replaces them with the ones provided.
 func (cb codeBlock) toCommands(serviceName, gcrURL string) ([]*exec.Cmd, error) {
 	var cmds []*exec.Cmd
 
@@ -79,17 +79,19 @@ func (cb codeBlock) toCommands(serviceName, gcrURL string) ([]*exec.Cmd, error)
 			line = line + l
 		}
 
-		line = os.ExpandEnv(line)
 		line = gcrURLRegexp.ReplaceAllString(line, gcrURL)
 		line = replaceServiceName(line, serviceName)
-		sp := strings.Split(line, " ")
 
 		var cmd *exec.Cmd
-		if sp[0] == "gcloud" {
-			a := append(util.GcloudCommonFlags, sp[1:]...)
-			cmd = exec.Command("gcloud", a...)
+		if gcloudCommandRegexp.MatchString(line) {
+			// Splitting command to add util.GcloudCommonFlags to front of command.
+			// TODO: Ideally want to use a library that splits commands according to bash specification.
+			sp := strings.Split(line, " ")
+			c := "gcloud " + strings.Join(append(util.GcloudCommonFlags, sp[1:]...), " ")
+
+			cmd = exec.Command("bash", "-c", c)
 		} else {
-			cmd = exec.Command(sp[0], sp[1:]...)
+			cmd = exec.Command("bash", "-c", line)
 		}
 
 		cmds = append(cmds, cmd)