Add exec (#10)

* Add exec

* Fix linux tests

* unnecessary dependency

* Dont prefix ExecOptions with I

* Consistency nits

* Respond to feedback

* Add toolrunner explanatory quote

* Format

packages/exec/src/exec.ts

@@ -0,0 +1,28 @@
+import * as im from './interfaces'
+import * as tr from './toolrunner'
+
+/**
+ * Exec a command.
+ * Output will be streamed to the live console.
+ * Returns promise with return code
+ *
+ * @param     commandLine        command to execute (can include additional args). Must be correctly escaped.
+ * @param     args               optional arguments for tool. Escaping is handled by the lib.
+ * @param     options            optional exec options.  See ExecOptions
+ * @returns   Promise<number>    exit code
+ */
+export async function exec(
+  commandLine: string,
+  args?: string[],
+  options?: im.ExecOptions
+): Promise<number> {
+  const commandArgs = tr.argStringToArray(commandLine)
+  if (commandArgs.length === 0) {
+    throw new Error(`Parameter 'commandLine' cannot be null or empty.`)
+  }
+  // Path to tool to execute should be first arg
+  const toolPath = commandArgs[0]
+  args = commandArgs.slice(1).concat(args || [])
+  const runner: tr.ToolRunner = new tr.ToolRunner(toolPath, args, options)
+  return runner.exec()
+}