diff --git a/src/Pure/Tools/phabricator.scala b/src/Pure/Tools/phabricator.scala
--- a/src/Pure/Tools/phabricator.scala
+++ b/src/Pure/Tools/phabricator.scala
@@ -1,468 +1,471 @@
 /*  Title:      Pure/Tools/phabricator.scala
     Author:     Makarius
 
 Support for Phabricator server, notably for Ubuntu 18.04 LTS.
 
 See also:
   - https://www.phacility.com/phabricator
   - https://secure.phabricator.com/book/phabricator
 */
 
 package isabelle
 
 
 import scala.util.matching.Regex
 
 
 object Phabricator
 {
   /** defaults **/
 
   /* required packages */
 
   val packages: List[String] =
     Build_Docker.packages :::
     List(
       // https://secure.phabricator.com/source/phabricator/browse/master/scripts/install/install_ubuntu.sh 15e6e2adea61
       "git", "mysql-server", "apache2", "libapache2-mod-php", "php", "php-mysql",
       "php-gd", "php-curl", "php-apcu", "php-cli", "php-json", "php-mbstring",
       // more packages
       "php-zip", "python-pygments", "ssh")
 
 
   /* global system resources */
 
   val www_user = "www-data"
 
   val daemon_user = "phabricator"
 
   val ssh_standard = 22
   val ssh_alternative1 = 222
   val ssh_alternative2 = 2222
 
 
   /* installation parameters */
 
   val default_name = "vcs"
 
   def phabricator_name(name: String = "", ext: String = ""): String =
     "phabricator" + (if (name.isEmpty) "" else "-" + name) + (if (ext.isEmpty) "" else "." + ext)
 
   def isabelle_phabricator_name(name: String = "", ext: String = ""): String =
     "isabelle-" + phabricator_name(name = name, ext = ext)
 
   def default_root(name: String): Path =
     Path.explode("/var/www") + Path.basic(phabricator_name(name = name))
 
   def default_repo(name: String): Path = default_root(name) + Path.basic("repo")
 
   val default_mailers: Path = Path.explode("mailers.json")
 
 
 
   /** global configuration **/
 
   val global_config = Path.explode("/etc/" + isabelle_phabricator_name(ext = "conf"))
 
   sealed case class Config(name: String, root: Path)
   {
     def home: Path = root + Path.explode(phabricator_name())
 
     def execute(command: String): Process_Result =
       Isabelle_System.bash("./bin/" + command, cwd = home.file, redirect = true).check
   }
 
   def read_config(): List[Config] =
   {
     if (global_config.is_file) {
       for (entry <- Library.trim_split_lines(File.read(global_config)) if entry.nonEmpty)
       yield {
         space_explode(':', entry) match {
           case List(name, root) => Config(name, Path.explode(root))
           case _ => error("Malformed config file " + global_config + "\nentry " + quote(entry))
         }
       }
     }
     else Nil
   }
 
   def write_config(configs: List[Config])
   {
     File.write(global_config,
       configs.map(config => config.name + ":" + config.root.implode).mkString("", "\n", "\n"))
   }
 
   def get_config(name: String): Config =
     read_config().find(config => config.name == name) getOrElse
       error("Bad Isabelle/Phabricator installation " + quote(name))
 
 
 
   /** setup **/
 
   def user_setup(name: String, description: String, ssh_setup: Boolean = false)
   {
     if (!Linux.user_exists(name)) {
       Linux.user_add(name, description = description, system = true, ssh_setup = ssh_setup)
     }
     else if (Linux.user_description(name) != description) {
       error("User " + quote(name) + " already exists --" +
         " for Phabricator it should have the description:\n  " + quote(description))
     }
   }
 
   def phabricator_setup(
     name: String = default_name,
     root: String = "",
     repo: String = "",
     package_update: Boolean = false,
     progress: Progress = No_Progress)
   {
     /* system environment */
 
     Linux.check_system_root()
 
     if (package_update) {
       Linux.package_update(progress = progress)
       Linux.check_reboot_required()
     }
 
     Linux.package_install(packages, progress = progress)
     Linux.check_reboot_required()
 
 
     /* users */
 
     if (name == daemon_user) {
       error("Clash of installation name with daemon user " + quote(daemon_user))
     }
 
     user_setup(daemon_user, "Phabricator Daemon User", ssh_setup = true)
     user_setup(name, "Phabricator SSH User")
 
 
     /* basic installation */
 
     progress.echo("\nPhabricator installation...")
 
     val root_path = if (root.nonEmpty) Path.explode(root) else default_root(name)
     val repo_path = if (repo.nonEmpty) Path.explode(repo) else default_repo(name)
 
     val configs = read_config()
 
     for (config <- configs if config.name == name) {
       error("Duplicate Phabricator installation " + quote(name) + " in " + config.root)
     }
 
     if (!Isabelle_System.bash("mkdir -p " + File.bash_path(root_path)).ok) {
       error("Failed to create root directory " + root_path)
     }
 
     progress.bash(cwd = root_path.file, echo = true,
       script = """
         set -e
         chown """ + Bash.string(www_user) + ":" + Bash.string(www_user) + """ .
         chmod 755 .
 
         git clone https://github.com/phacility/libphutil.git
         git clone https://github.com/phacility/arcanist.git
         git clone https://github.com/phacility/phabricator.git
       """).check
 
     val config = Config(name, root_path)
     write_config(configs ::: List(config))
 
     config.execute("config set pygments.enabled true")
 
 
     /* local repository directory */
 
     if (!Isabelle_System.bash("mkdir -p " + File.bash_path(repo_path)).ok) {
       error("Failed to create local repository directory " + repo_path)
     }
 
     Isabelle_System.bash(cwd = repo_path.file,
       script = """
         set -e
         chown -R """ + Bash.string(daemon_user) + ":" + Bash.string(daemon_user) + """ .
         chmod 755 .
       """).check
 
     config.execute("config set repository.default-local-path " + File.bash_path(repo_path))
 
 
     /* MySQL setup */
 
     progress.echo("\nMySQL setup...")
 
     File.write(Path.explode("/etc/mysql/mysql.conf.d/" + phabricator_name(ext = "cnf")),
 """[mysqld]
 max_allowed_packet = 32M
 innodb_buffer_pool_size = 1600M
 local_infile = 0
 """)
 
     Linux.service_restart("mysql")
 
 
     def mysql_conf(R: Regex): Option[String] =
       split_lines(File.read(Path.explode("/etc/mysql/debian.cnf"))).collectFirst({ case R(a) => a })
 
     for (user <- mysql_conf("""^user\s*=\s*(\S*)\s*$""".r)) {
       config.execute("config set mysql.user " + Bash.string(user))
     }
 
     for (pass <- mysql_conf("""^password\s*=\s*(\S*)\s*$""".r)) {
       config.execute("config set mysql.pass " + Bash.string(pass))
     }
 
     config.execute("config set storage.default-namespace " +
       Bash.string(phabricator_name(name = name).replace("-", "_")))
 
     config.execute("config set storage.mysql-engine.max-size 8388608")
 
     progress.bash("./bin/storage upgrade --force", cwd = config.home.file, echo = true).check
 
 
     /* SSH hosting */
 
     progress.echo("\nSSH hosting setup...")
 
     val ssh_port = ssh_alternative2
 
     config.execute("config set diffusion.ssh-user " + Bash.string(name))
     config.execute("config set diffusion.ssh-port " + ssh_port)
 
     val sudoers_file = Path.explode("/etc/sudoers.d") + Path.basic(isabelle_phabricator_name())
     File.write(sudoers_file,
       www_user + " ALL=(" + daemon_user + ") SETENV: NOPASSWD: /usr/bin/git, /usr/bin/hg, /usr/bin/ssh, /usr/bin/id\n" +
       name + " ALL=(" + daemon_user + ") SETENV: NOPASSWD: /usr/bin/git, /usr/bin/git-upload-pack, /usr/bin/git-receive-pack, /usr/bin/hg, /usr/bin/svnserve, /usr/bin/ssh, /usr/bin/id\n")
 
     Isabelle_System.bash("chmod 0440 " + File.bash_path(sudoers_file)).check
 
 
     /* PHP setup */
 
     val php_version =
       Isabelle_System.bash("""php --run 'echo PHP_MAJOR_VERSION . "." . PHP_MINOR_VERSION;'""")
         .check.out
 
     val php_conf =
       Path.explode("/etc/php") + Path.basic(php_version) +  // educated guess
         Path.explode("apache2/conf.d") +
         Path.basic(isabelle_phabricator_name(ext = "ini"))
 
     File.write(php_conf,
       "post_max_size = 32M\n" +
       "opcache.validate_timestamps = 0\n" +
       "memory_limit = 512M\n")
 
 
     /* Apache setup */
 
     progress.echo("\nApache setup...")
 
     val apache_root = Path.explode("/etc/apache2")
     val apache_sites = apache_root + Path.explode("sites-available")
 
     if (!apache_sites.is_dir) error("Bad Apache sites directory " + apache_sites)
 
     val server_name = phabricator_name(name = name, ext = "lvh.me")  // alias for "localhost" for testing
     val server_url = "http://" + server_name
 
     File.write(apache_sites + Path.basic(isabelle_phabricator_name(name = name, ext = "conf")),
 """<VirtualHost *:80>
     ServerName """ + server_name + """
     ServerAdmin webmaster@localhost
     DocumentRoot """ + config.home.implode + """/webroot
 
     ErrorLog ${APACHE_LOG_DIR}/error.log
     RewriteEngine on
     RewriteRule ^(.*)$  /index.php?__path__=$1  [B,L,QSA]
 </VirtualHost>
 
 # vim: syntax=apache ts=4 sw=4 sts=4 sr noet
 """)
 
     Isabelle_System.bash( """
       set -e
       a2enmod rewrite
       a2ensite """ + Bash.string(isabelle_phabricator_name(name = name))).check
 
     config.execute("config set phabricator.base-uri " + Bash.string(server_url))
 
     Linux.service_restart("apache2")
 
 
     /* PHP daemon */
 
     progress.echo("\nPHP daemon setup...")
 
     config.execute("config set phd.user " + Bash.string(daemon_user))
 
     Linux.service_install(isabelle_phabricator_name(name = name),
 """[Unit]
 Description=PHP daemon for Isabelle/Phabricator """ + quote(name) + """
 After=syslog.target network.target apache2.service mysql.service
 
 [Service]
 Type=oneshot
 User=""" + daemon_user + """
 Group=""" + daemon_user + """
 Environment=PATH=/sbin:/usr/sbin:/usr/local/sbin:/usr/local/bin:/usr/bin:/bin
 ExecStart=""" + config.home.implode + """/bin/phd start
 ExecStop=""" + config.home.implode + """/bin/phd stop
 RemainAfterExit=yes
 
 [Install]
 WantedBy=multi-user.target
 """)
 
 
     progress.echo("\nDONE\nWeb configuration via " + server_url)
   }
 
 
   /* Isabelle tool wrapper */
 
   val isabelle_tool1 =
     Isabelle_Tool("phabricator_setup", "setup Phabricator server on Ubuntu Linux", args =>
     {
       var repo = ""
       var package_update = false
       var root = ""
 
       val getopts =
         Getopts("""
 Usage: isabelle phabricator_setup [OPTIONS] [NAME]
 
   Options are:
     -R DIR       repository directory (default: """ + default_repo("NAME") + """)
     -U           full update of system packages before installation
     -r DIR       installation root directory (default: """ + default_root("NAME") + """)
 
   Install Phabricator as Ubuntu LAMP application (Linux, Apache, MySQL, PHP).
 
   Slogan: "Discuss. Plan. Code. Review. Test.
   Every application your project needs, all in one tool."
 
   The installation NAME (default: """ + quote(default_name) + """) is mapped to
   a regular Unix user and used for public SSH access.
 """,
           "R:" -> (arg => repo = arg),
           "U" -> (_ => package_update = true),
           "r:" -> (arg => root = arg))
 
       val more_args = getopts(args)
 
       val name =
         more_args match {
           case Nil => default_name
           case List(name) => name
           case _ => getopts.usage()
         }
 
       val progress = new Console_Progress
 
       phabricator_setup(name, root = root, repo = repo,
         package_update = package_update, progress = progress)
     })
 
 
 
   /** setup mail **/
 
   val mailers_template: String =
 """[
   {
     "key": "example.org",
     "type": "smtp",
     "options": {
       "host": "mail.example.org",
       "port": 465,
       "user": "phabricator@example.org",
       "password": "********",
       "protocol": "ssl",
       "message-id": true
     }
   }
 ]"""
 
   def phabricator_setup_mail(
     name: String = default_name,
     config_file: Option[Path] = None,
     test_user: String = "",
     progress: Progress = No_Progress)
   {
     Linux.check_system_root()
 
     val config = get_config(name)
     val default_config_file = config.root + default_mailers
 
     val mail_config = config_file getOrElse default_config_file
 
     def setup_mail
     {
       progress.echo("Using mail configuration from " + mail_config)
       config.execute("config set cluster.mailers --stdin < " + File.bash_path(mail_config))
 
       if (test_user.nonEmpty) {
         progress.echo("Sending test mail to " + quote(test_user))
         progress.bash(cwd = config.home.file, echo = true,
           script = """echo "Test from Phabricator ($(date))" | ./bin/mail send-test --subject "Test" --to """ +
             Bash.string(test_user)).check
       }
     }
 
     if (config_file.isEmpty) {
       if (!default_config_file.is_file) {
         File.write(default_config_file, mailers_template)
         Isabelle_System.bash("chmod 600 " + File.bash_path(default_config_file)).check
       }
       if (File.read(default_config_file) == mailers_template) {
         progress.echo(
-          "Please invoke the tool again, after providing details in:\n  " +
-          default_config_file.implode)
+"""
+Please invoke the tool again, after providing details in
+  """ + default_config_file.implode + """
+
+See also section "Mailer: SMTP" in
+  https://secure.phabricator.com/book/phabricator/article/configuring_outbound_email
+""")
       }
       else setup_mail
     }
     else setup_mail
   }
 
 
   /* Isabelle tool wrapper */
 
   val isabelle_tool2 =
     Isabelle_Tool("phabricator_setup_mail",
       "setup mail configuration for existing Phabricator server", args =>
     {
       var test_user = ""
       var name = default_name
       var config_file: Option[Path] = None
 
       val getopts =
         Getopts("""
 Usage: isabelle phabricator_setup_mail [OPTIONS]
 
   Options are:
     -T USER      send test mail to Phabricator user
     -f FILE      config file (default: """ + default_mailers + """ within installation root)
     -n NAME      Phabricator installation name (default: """ + quote(default_name) + """)
 
-  Provide mail configuration for existing Phabricator installation. See also
-  https://secure.phabricator.com/book/phabricator/article/configuring_outbound_email
-  (notably section "Mailer: SMTP").
+  Provide mail configuration for existing Phabricator installation.
 """,
           "T:" -> (arg => test_user = arg),
           "f:" -> (arg => config_file = Some(Path.explode(arg))),
           "n:" -> (arg => name = arg))
 
       val more_args = getopts(args)
       if (more_args.nonEmpty) getopts.usage()
 
       val progress = new Console_Progress
 
       phabricator_setup_mail(name = name, config_file = config_file,
         test_user = test_user, progress = progress)
     })
 }