diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/CommandExecutor.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/CommandExecutor.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,898 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.nashorn.internal.runtime;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.StreamTokenizer;
+import java.io.StringReader;
+import java.lang.ProcessBuilder.Redirect;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import static jdk.nashorn.internal.runtime.CommandExecutor.RedirectType.*;
+import static jdk.nashorn.internal.runtime.ECMAErrors.rangeError;
+
+/**
+ * The CommandExecutor class provides support for Nashorn's $EXEC
+ * builtin function. CommandExecutor provides support for command parsing,
+ * I/O redirection, piping, completion timeouts, # comments, and simple
+ * environment variable management (cd, setenv, and unsetenv).
+ */
+class CommandExecutor {
+    // Size of byte buffers used for piping.
+    private static final int BUFFER_SIZE = 1024;
+
+    // Test to see if running on Windows.
+    private static final boolean IS_WINDOWS =
+        AccessController.doPrivileged((PrivilegedAction<Boolean>)() -> {
+        return System.getProperty("os.name").contains("Windows");
+    });
+
+    // Cygwin drive alias prefix.
+    private static final String CYGDRIVE = "/cygdrive/";
+
+    // User's home directory
+    private static final String HOME_DIRECTORY =
+        AccessController.doPrivileged((PrivilegedAction<String>)() -> {
+        return System.getProperty("user.home");
+    });
+
+    // Various types of standard redirects.
+    enum RedirectType {
+        NO_REDIRECT,
+        REDIRECT_INPUT,
+        REDIRECT_OUTPUT,
+        REDIRECT_OUTPUT_APPEND,
+        REDIRECT_ERROR,
+        REDIRECT_ERROR_APPEND,
+        REDIRECT_OUTPUT_ERROR_APPEND,
+        REDIRECT_ERROR_TO_OUTPUT
+    };
+
+    // Prefix strings to standard redirects.
+    private static final String[] redirectPrefixes = new String[] {
+        "<",
+        "0<",
+        ">",
+        "1>",
+        ">>",
+        "1>>",
+        "2>",
+        "2>>",
+        "&>",
+        "2>&1"
+    };
+
+    // Map from redirectPrefixes to RedirectType.
+    private static final RedirectType[] redirects = new RedirectType[] {
+        REDIRECT_INPUT,
+        REDIRECT_INPUT,
+        REDIRECT_OUTPUT,
+        REDIRECT_OUTPUT,
+        REDIRECT_OUTPUT_APPEND,
+        REDIRECT_OUTPUT_APPEND,
+        REDIRECT_ERROR,
+        REDIRECT_ERROR_APPEND,
+        REDIRECT_OUTPUT_ERROR_APPEND,
+        REDIRECT_ERROR_TO_OUTPUT
+    };
+
+    /**
+     * The RedirectInfo class handles checking the next token in a command
+     * to see if it contains a redirect.  If the redirect file does not butt
+     * against the prefix, then the next token is consumed.
+     */
+    private static class RedirectInfo {
+        // true if a redirect was encountered on the current command.
+        private boolean hasRedirects;
+        // Redirect.PIPE or an input redirect from the command line.
+        private Redirect inputRedirect;
+        // Redirect.PIPE or an output redirect from the command line.
+        private Redirect outputRedirect;
+        // Redirect.PIPE or an error redirect from the command line.
+        private Redirect errorRedirect;
+        // true if the error stream should be merged with output.
+        private boolean mergeError;
+
+        RedirectInfo() {
+            this.hasRedirects = false;
+            this.inputRedirect = Redirect.PIPE;
+            this.outputRedirect = Redirect.PIPE;
+            this.errorRedirect = Redirect.PIPE;
+            this.mergeError = false;
+        }
+
+        /**
+         * check - tests to see if the current token contains a redirect
+         * @param token    current command line token
+         * @param iterator current command line iterator
+         * @param cwd      current working directory
+         * @return true if token is consumed
+         */
+        boolean check(String token, final Iterator<String> iterator, final String cwd) {
+            // Iterate through redirect prefixes to file a match.
+            for (int i = 0; i < redirectPrefixes.length; i++) {
+               final String prefix = redirectPrefixes[i];
+
+               // If a match is found.
+                if (token.startsWith(prefix)) {
+                    // Indicate we have at least one redirect (efficiency.)
+                    hasRedirects = true;
+                    // Map prefix to RedirectType.
+                    final RedirectType redirect = redirects[i];
+                    // Strip prefix from token
+                    token = token.substring(prefix.length());
+
+                    // Get file from either current or next token.
+                    File file = null;
+                    if (redirect != REDIRECT_ERROR_TO_OUTPUT) {
+                        // Nothing left of current token.
+                        if (token.length() == 0) {
+                            if (iterator.hasNext()) {
+                                // Use next token.
+                                token = iterator.next();
+                            } else {
+                                // Send to null device if not provided.
+                                token = IS_WINDOWS ? "NUL:" : "/dev/null";
+                            }
+                        }
+
+                        // Redirect file.
+                        file = resolvePath(cwd, token).toFile();
+                    }
+
+                    // Define redirect based on prefix.
+                    switch (redirect) {
+                        case REDIRECT_INPUT:
+                            inputRedirect = Redirect.from(file);
+                            break;
+                        case REDIRECT_OUTPUT:
+                            outputRedirect = Redirect.to(file);
+                            break;
+                        case REDIRECT_OUTPUT_APPEND:
+                            outputRedirect = Redirect.appendTo(file);
+                            break;
+                        case REDIRECT_ERROR:
+                            errorRedirect = Redirect.to(file);
+                            break;
+                        case REDIRECT_ERROR_APPEND:
+                            errorRedirect = Redirect.appendTo(file);
+                            break;
+                        case REDIRECT_OUTPUT_ERROR_APPEND:
+                            outputRedirect = Redirect.to(file);
+                            errorRedirect = Redirect.to(file);
+                            mergeError = true;
+                            break;
+                        case REDIRECT_ERROR_TO_OUTPUT:
+                            mergeError = true;
+                            break;
+                        default:
+                            return false;
+                    }
+
+                    // Indicate token is consumed.
+                    return true;
+                }
+            }
+
+            // No redirect found.
+            return false;
+        }
+
+        /**
+         * apply - apply the redirects to the current ProcessBuilder.
+         * @param pb current ProcessBuilder
+         */
+        void apply(final ProcessBuilder pb) {
+            // Only if there was redirects (saves new structure in ProcessBuilder.)
+            if (hasRedirects) {
+                // If output and error are the same file then merge.
+                final File outputFile = outputRedirect.file();
+                final File errorFile = errorRedirect.file();
+
+                if (outputFile != null && outputFile.equals(errorFile)) {
+                    mergeError = true;
+                }
+
+                // Apply redirects.
+                pb.redirectInput(inputRedirect);
+                pb.redirectOutput(outputRedirect);
+                pb.redirectError(errorRedirect);
+                pb.redirectErrorStream(mergeError);
+            }
+        }
+    }
+
+    /**
+     * The Piper class is responsible for copying from an InputStream to an
+     * OutputStream without blocking the current thread.
+     */
+    private static class Piper implements java.lang.Runnable {
+        // Stream to copy from.
+        private final InputStream input;
+        // Stream to copy to.
+        private final OutputStream output;
+
+        private final Thread thread;
+
+        Piper(final InputStream input, final OutputStream output) {
+            this.input = input;
+            this.output = output;
+            this.thread = new Thread(this, "$EXEC Piper");
+        }
+
+        /**
+         * start - start the Piper in a new daemon thread
+         * @return this Piper
+         */
+        Piper start() {
+            thread.setDaemon(true);
+            thread.start();
+            return this;
+        }
+
+        /**
+         * run - thread action
+         */
+        @Override
+        public void run() {
+            try {
+                // Buffer for copying.
+                final byte[] b = new byte[BUFFER_SIZE];
+                // Read from the InputStream until EOF.
+                int read;
+                while (-1 < (read = input.read(b, 0, b.length))) {
+                    // Write available date to OutputStream.
+                    output.write(b, 0, read);
+                }
+            } catch (final Exception e) {
+                // Assume the worst.
+                throw new RuntimeException("Broken pipe", e);
+            } finally {
+                // Make sure the streams are closed.
+                try {
+                    input.close();
+                } catch (final IOException e) {
+                    // Don't care.
+                }
+                try {
+                    output.close();
+                } catch (final IOException e) {
+                    // Don't care.
+                }
+            }
+        }
+
+        public void join() throws InterruptedException {
+            thread.join();
+        }
+
+        // Exit thread.
+    }
+
+    // Process exit statuses.
+    static final int EXIT_SUCCESS  =  0;
+    static final int EXIT_FAILURE  =  1;
+
+    // Copy of environment variables used by all processes.
+    private  Map<String, String> environment;
+    // Input string if provided on CommandExecutor call.
+    private String inputString;
+    // Output string if required from CommandExecutor call.
+    private String outputString;
+    // Error string if required from CommandExecutor call.
+    private String errorString;
+    // Last process exit code.
+    private int exitCode;
+
+    // Input stream if provided on CommandExecutor call.
+    private InputStream inputStream;
+    // Output stream if provided on CommandExecutor call.
+    private OutputStream outputStream;
+    // Error stream if provided on CommandExecutor call.
+    private OutputStream errorStream;
+
+    // Ordered collection of current or piped ProcessBuilders.
+    private List<ProcessBuilder> processBuilders = new ArrayList<>();
+
+    CommandExecutor() {
+        this.environment = new HashMap<>();
+        this.inputString = "";
+        this.outputString = "";
+        this.errorString = "";
+        this.exitCode = EXIT_SUCCESS;
+        this.inputStream = null;
+        this.outputStream = null;
+        this.errorStream = null;
+        this.processBuilders = new ArrayList<>();
+    }
+
+    /**
+     * envVarValue - return the value of the environment variable key, or
+     * deflt if not found.
+     * @param key   name of environment variable
+     * @param deflt value to return if not found
+     * @return value of the environment variable
+     */
+    private String envVarValue(final String key, final String deflt) {
+        return environment.getOrDefault(key, deflt);
+    }
+
+    /**
+     * envVarLongValue - return the value of the environment variable key as a
+     * long value.
+     * @param key name of environment variable
+     * @return long value of the environment variable
+     */
+    private long envVarLongValue(final String key) {
+        try {
+            return Long.parseLong(envVarValue(key, "0"));
+        } catch (final NumberFormatException ex) {
+            return 0L;
+        }
+    }
+
+    /**
+     * envVarBooleanValue - return the value of the environment variable key as a
+     * boolean value.  true if the value was non-zero, false otherwise.
+     * @param key name of environment variable
+     * @return boolean value of the environment variable
+     */
+    private boolean envVarBooleanValue(final String key) {
+        return envVarLongValue(key) != 0;
+    }
+
+    /**
+     * stripQuotes - strip quotes from token if present. Quoted tokens kept
+     * quotes to prevent search for redirects.
+     * @param token token to strip
+     * @return stripped token
+     */
+    private static String stripQuotes(String token) {
+        if ((token.startsWith("\"") && token.endsWith("\"")) ||
+             token.startsWith("\'") && token.endsWith("\'")) {
+            token = token.substring(1, token.length() - 1);
+        }
+        return token;
+    }
+
+    /**
+     * resolvePath - resolves a path against a current working directory.
+     * @param cwd      current working directory
+     * @param fileName name of file or directory
+     * @return resolved Path to file
+     */
+    private static Path resolvePath(final String cwd, final String fileName) {
+        return Paths.get(sanitizePath(cwd)).resolve(fileName).normalize();
+    }
+
+    /**
+     * builtIn - checks to see if the command is a builtin and performs
+     * appropriate action.
+     * @param cmd current command
+     * @param cwd current working directory
+     * @return true if was a builtin command
+     */
+    private boolean builtIn(final List<String> cmd, final String cwd) {
+        switch (cmd.get(0)) {
+            // Set current working directory.
+            case "cd":
+                final boolean cygpath = IS_WINDOWS && cwd.startsWith(CYGDRIVE);
+                // If zero args then use home directory as cwd else use first arg.
+                final String newCWD = cmd.size() < 2 ? HOME_DIRECTORY : cmd.get(1);
+                // Normalize the cwd
+                final Path cwdPath = resolvePath(cwd, newCWD);
+
+                // Check if is a directory.
+                final File file = cwdPath.toFile();
+                if (!file.exists()) {
+                    reportError("file.not.exist", file.toString());
+                    return true;
+                } else if (!file.isDirectory()) {
+                    reportError("not.directory", file.toString());
+                    return true;
+                }
+
+                // Set PWD environment variable to be picked up as cwd.
+                // Make sure Cygwin paths look like Unix paths.
+                String scwd = cwdPath.toString();
+                if (cygpath && scwd.length() >= 2 &&
+                        Character.isLetter(scwd.charAt(0)) && scwd.charAt(1) == ':') {
+                    scwd = CYGDRIVE + Character.toLowerCase(scwd.charAt(0)) + "/" + scwd.substring(2);
+                }
+                environment.put("PWD", scwd);
+                return true;
+
+            // Set an environment variable.
+            case "setenv":
+                if (3 <= cmd.size()) {
+                    final String key = cmd.get(1);
+                    final String value = cmd.get(2);
+                    environment.put(key, value);
+                }
+
+                return true;
+
+            // Unset an environment variable.
+            case "unsetenv":
+                if (2 <= cmd.size()) {
+                    final String key = cmd.get(1);
+                    environment.remove(key);
+                }
+
+                return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * preprocessCommand - scan the command for redirects, and sanitize the
+     * executable path
+     * @param tokens       command tokens
+     * @param cwd          current working directory
+     * @param redirectInfo redirection information
+     * @return tokens remaining for actual command
+     */
+    private List<String>  preprocessCommand(final List<String> tokens,
+            final String cwd, final RedirectInfo redirectInfo) {
+        // Tokens remaining for actual command.
+        final List<String> command = new ArrayList<>();
+
+        // iterate through all tokens.
+        final Iterator<String> iterator = tokens.iterator();
+        while (iterator.hasNext()) {
+            final String token = iterator.next();
+
+            // Check if is a redirect.
+            if (redirectInfo.check(token, iterator, cwd)) {
+                // Don't add to the command.
+                continue;
+            }
+
+            // Strip quotes and add to command.
+            command.add(stripQuotes(token));
+        }
+
+        if (command.size() > 0) {
+            command.set(0, sanitizePath(command.get(0)));
+        }
+
+        return command;
+    }
+
+    /**
+     * Sanitize a path in case the underlying platform is Cygwin. In that case,
+     * convert from the {@code /cygdrive/x} drive specification to the usual
+     * Windows {@code X:} format.
+     *
+     * @param d a String representing a path
+     * @return a String representing the same path in a form that can be
+     *         processed by the underlying platform
+     */
+    private static String sanitizePath(final String d) {
+        if (!IS_WINDOWS || (IS_WINDOWS && !d.startsWith(CYGDRIVE))) {
+            return d;
+        }
+        final String pd = d.substring(CYGDRIVE.length());
+        if (pd.length() >= 2 && pd.charAt(1) == '/') {
+            // drive letter plus / -> convert /cygdrive/x/... to X:/...
+            return pd.charAt(0) + ":" + pd.substring(1);
+        } else if (pd.length() == 1) {
+            // just drive letter -> convert /cygdrive/x to X:
+            return pd.charAt(0) + ":";
+        }
+        // remaining case: /cygdrive/ -> can't convert
+        return d;
+    }
+
+    /**
+     * createProcessBuilder - create a ProcessBuilder for the command.
+     * @param command      command tokens
+     * @param cwd          current working directory
+     * @param redirectInfo redirect information
+     */
+    private void createProcessBuilder(final List<String> command,
+            final String cwd, final RedirectInfo redirectInfo) {
+        // Create new ProcessBuilder.
+        final ProcessBuilder pb = new ProcessBuilder(command);
+        // Set current working directory.
+        pb.directory(new File(sanitizePath(cwd)));
+
+        // Map environment variables.
+        final Map<String, String> processEnvironment = pb.environment();
+        processEnvironment.clear();
+        processEnvironment.putAll(environment);
+
+        // Apply redirects.
+        redirectInfo.apply(pb);
+        // Add to current list of commands.
+        processBuilders.add(pb);
+    }
+
+    /**
+     * command - process the command
+     * @param tokens  tokens of the command
+     * @param isPiped true if the output of this command should be piped to the next
+     */
+    private void command(final List<String> tokens, final boolean isPiped) {
+        // Test to see if we should echo the command to output.
+        if (envVarBooleanValue("JJS_ECHO")) {
+            System.out.println(String.join(" ", tokens));
+        }
+
+        // Get the current working directory.
+        final String cwd = envVarValue("PWD", HOME_DIRECTORY);
+        // Preprocess the command for redirects.
+        final RedirectInfo redirectInfo = new RedirectInfo();
+        final List<String> command = preprocessCommand(tokens, cwd, redirectInfo);
+
+        // Skip if empty or a built in.
+        if (command.isEmpty() || builtIn(command, cwd)) {
+            return;
+        }
+
+        // Create ProcessBuilder with cwd and redirects set.
+        createProcessBuilder(command, cwd, redirectInfo);
+
+        // If piped, wait for the next command.
+        if (isPiped) {
+            return;
+        }
+
+        // Fetch first and last ProcessBuilder.
+        final ProcessBuilder firstProcessBuilder = processBuilders.get(0);
+        final ProcessBuilder lastProcessBuilder = processBuilders.get(processBuilders.size() - 1);
+
+        // Determine which streams have not be redirected from pipes.
+        boolean inputIsPipe = firstProcessBuilder.redirectInput() == Redirect.PIPE;
+        boolean outputIsPipe = lastProcessBuilder.redirectOutput() == Redirect.PIPE;
+        boolean errorIsPipe = lastProcessBuilder.redirectError() == Redirect.PIPE;
+        final boolean inheritIO = envVarBooleanValue("JJS_INHERIT_IO");
+
+        // If not redirected and inputStream is current processes' input.
+        if (inputIsPipe && (inheritIO || inputStream == System.in)) {
+            // Inherit current processes' input.
+            firstProcessBuilder.redirectInput(Redirect.INHERIT);
+            inputIsPipe = false;
+        }
+
+        // If not redirected and outputStream is current processes' output.
+        if (outputIsPipe && (inheritIO || outputStream == System.out)) {
+            // Inherit current processes' output.
+            lastProcessBuilder.redirectOutput(Redirect.INHERIT);
+            outputIsPipe = false;
+        }
+
+        // If not redirected and errorStream is current processes' error.
+        if (errorIsPipe && (inheritIO || errorStream == System.err)) {
+            // Inherit current processes' error.
+            lastProcessBuilder.redirectError(Redirect.INHERIT);
+            errorIsPipe = false;
+        }
+
+        // Start the processes.
+        final List<Process> processes = new ArrayList<>();
+        for (final ProcessBuilder pb : processBuilders) {
+            try {
+                processes.add(pb.start());
+            } catch (final IOException ex) {
+                reportError("unknown.command", String.join(" ", pb.command()));
+                return;
+            }
+        }
+
+        // Clear processBuilders for next command.
+        processBuilders.clear();
+
+        // Get first and last process.
+        final Process firstProcess = processes.get(0);
+        final Process lastProcess = processes.get(processes.size() - 1);
+
+        // Prepare for string based i/o if no redirection or provided streams.
+        ByteArrayOutputStream byteOutputStream = null;
+        ByteArrayOutputStream byteErrorStream = null;
+
+        final List<Piper> piperThreads = new ArrayList<>();
+
+        // If input is not redirected.
+        if (inputIsPipe) {
+            // If inputStream other than System.in is provided.
+            if (inputStream != null) {
+                // Pipe inputStream to first process output stream.
+                piperThreads.add(new Piper(inputStream, firstProcess.getOutputStream()).start());
+            } else {
+                // Otherwise assume an input string has been provided.
+                piperThreads.add(new Piper(new ByteArrayInputStream(inputString.getBytes()), firstProcess.getOutputStream()).start());
+            }
+        }
+
+        // If output is not redirected.
+        if (outputIsPipe) {
+            // If outputStream other than System.out is provided.
+            if (outputStream != null ) {
+                // Pipe outputStream from last process input stream.
+                piperThreads.add(new Piper(lastProcess.getInputStream(), outputStream).start());
+            } else {
+                // Otherwise assume an output string needs to be prepared.
+                byteOutputStream = new ByteArrayOutputStream(BUFFER_SIZE);
+                piperThreads.add(new Piper(lastProcess.getInputStream(), byteOutputStream).start());
+            }
+        }
+
+        // If error is not redirected.
+        if (errorIsPipe) {
+            // If errorStream other than System.err is provided.
+            if (errorStream != null) {
+                piperThreads.add(new Piper(lastProcess.getErrorStream(), errorStream).start());
+            } else {
+                // Otherwise assume an error string needs to be prepared.
+                byteErrorStream = new ByteArrayOutputStream(BUFFER_SIZE);
+                piperThreads.add(new Piper(lastProcess.getErrorStream(), byteErrorStream).start());
+            }
+        }
+
+        // Pipe commands in between.
+        for (int i = 0, n = processes.size() - 1; i < n; i++) {
+            final Process prev = processes.get(i);
+            final Process next = processes.get(i + 1);
+            piperThreads.add(new Piper(prev.getInputStream(), next.getOutputStream()).start());
+        }
+
+        // Wind up processes.
+        try {
+            // Get the user specified timeout.
+            final long timeout = envVarLongValue("JJS_TIMEOUT");
+
+            // If user specified timeout (milliseconds.)
+            if (timeout != 0) {
+                // Wait for last process, with timeout.
+                if (lastProcess.waitFor(timeout, TimeUnit.MILLISECONDS)) {
+                    // Get exit code of last process.
+                    exitCode = lastProcess.exitValue();
+                } else {
+                    reportError("timeout", Long.toString(timeout));
+                 }
+            } else {
+                // Wait for last process and get exit code.
+                exitCode = lastProcess.waitFor();
+            }
+            // Wait for all piper threads to terminate
+            for (final Piper piper : piperThreads) {
+                piper.join();
+            }
+
+            // Accumulate the output and error streams.
+            outputString += byteOutputStream != null ? byteOutputStream.toString() : "";
+            errorString += byteErrorStream != null ? byteErrorStream.toString() : "";
+        } catch (final InterruptedException ex) {
+            // Kill any living processes.
+            processes.stream().forEach(p -> {
+                if (p.isAlive()) {
+                    p.destroy();
+                }
+
+                // Get the first error code.
+                exitCode = exitCode == 0 ? p.exitValue() : exitCode;
+            });
+        }
+
+        // If we got a non-zero exit code then possibly throw an exception.
+        if (exitCode != 0 && envVarBooleanValue("JJS_THROW_ON_EXIT")) {
+            throw rangeError("exec.returned.non.zero", ScriptRuntime.safeToString(exitCode));
+        }
+    }
+
+    /**
+     * createTokenizer - build up StreamTokenizer for the command script
+     * @param script command script to parsed
+     * @return StreamTokenizer for command script
+     */
+    private static StreamTokenizer createTokenizer(final String script) {
+        final StreamTokenizer tokenizer = new StreamTokenizer(new StringReader(script));
+        tokenizer.resetSyntax();
+        // Default all characters to word.
+        tokenizer.wordChars(0, 255);
+        // Spaces and special characters are white spaces.
+        tokenizer.whitespaceChars(0, ' ');
+        // Ignore # comments.
+        tokenizer.commentChar('#');
+        // Handle double and single quote strings.
+        tokenizer.quoteChar('"');
+        tokenizer.quoteChar('\'');
+        // Need to recognize the end of a command.
+        tokenizer.eolIsSignificant(true);
+        // Command separator.
+        tokenizer.ordinaryChar(';');
+        // Pipe separator.
+        tokenizer.ordinaryChar('|');
+
+        return tokenizer;
+    }
+
+    /**
+     * process - process a command string
+     * @param script command script to parsed
+     */
+    void process(final String script) {
+        // Build up StreamTokenizer for the command script.
+        final StreamTokenizer tokenizer = createTokenizer(script);
+
+        // Prepare to accumulate command tokens.
+        final List<String> command = new ArrayList<>();
+        // Prepare to acumulate partial tokens joined with "\ ".
+        final StringBuilder sb = new StringBuilder();
+
+        try {
+            // Fetch next token until end of script.
+            while (tokenizer.nextToken() != StreamTokenizer.TT_EOF) {
+                // Next word token.
+                String token = tokenizer.sval;
+
+                // If special token.
+                if (token == null) {
+                    // Flush any partial token.
+                    if (sb.length() != 0) {
+                        command.add(sb.append(token).toString());
+                        sb.setLength(0);
+                    }
+
+                    // Process a completed command.
+                    // Will be either ';' (command end) or '|' (pipe), true if '|'.
+                    command(command, tokenizer.ttype == '|');
+
+                    if (exitCode != EXIT_SUCCESS) {
+                        return;
+                    }
+
+                    // Start with a new set of tokens.
+                    command.clear();
+                } else if (token.endsWith("\\")) {
+                    // Backslash followed by space.
+                    sb.append(token.substring(0, token.length() - 1)).append(' ');
+                } else if (sb.length() == 0) {
+                    // If not a word then must be a quoted string.
+                    if (tokenizer.ttype != StreamTokenizer.TT_WORD) {
+                        // Quote string, sb is free to use (empty.)
+                        sb.append((char)tokenizer.ttype);
+                        sb.append(token);
+                        sb.append((char)tokenizer.ttype);
+                        token = sb.toString();
+                        sb.setLength(0);
+                    }
+
+                    command.add(token);
+                } else {
+                    // Partial token pending.
+                    command.add(sb.append(token).toString());
+                    sb.setLength(0);
+                }
+            }
+        } catch (final IOException ex) {
+            // Do nothing.
+        }
+
+        // Partial token pending.
+        if (sb.length() != 0) {
+            command.add(sb.toString());
+        }
+
+        // Process last command.
+        command(command, false);
+    }
+
+    /**
+     * process - process a command array of strings
+     * @param tokens command script to be processed
+     */
+    void process(final List<String> tokens) {
+        // Prepare to accumulate command tokens.
+        final List<String> command = new ArrayList<>();
+
+        // Iterate through tokens.
+        final Iterator<String> iterator = tokens.iterator();
+        while (iterator.hasNext() && exitCode == EXIT_SUCCESS) {
+            // Next word token.
+            final String token = iterator.next();
+
+            if (token == null) {
+                continue;
+            }
+
+            switch (token) {
+                case "|":
+                    // Process as a piped command.
+                    command(command, true);
+                    // Start with a new set of tokens.
+                    command.clear();
+
+                    continue;
+                case ";":
+                    // Process as a normal command.
+                    command(command, false);
+                    // Start with a new set of tokens.
+                    command.clear();
+
+                    continue;
+            }
+
+            command.add(token);
+        }
+
+        // Process last command.
+        command(command, false);
+    }
+
+    void reportError(final String msg, final String object) {
+        errorString += ECMAErrors.getMessage("range.error.exec." + msg, object);
+        exitCode = EXIT_FAILURE;
+    }
+
+    String getOutputString() {
+        return outputString;
+    }
+
+    String getErrorString() {
+        return errorString;
+    }
+
+    int getExitCode() {
+        return exitCode;
+    }
+
+    void setEnvironment(final Map<String, String> environment) {
+        this.environment = environment;
+    }
+
+    void setInputStream(final InputStream inputStream) {
+        this.inputStream = inputStream;
+    }
+
+    void setInputString(final String inputString) {
+        this.inputString = inputString;
+    }
+
+    void setOutputStream(final OutputStream outputStream) {
+        this.outputStream = outputStream;
+    }
+
+    void setErrorStream(final OutputStream errorStream) {
+        this.errorStream = errorStream;
+    }
+}