src/Pure/General/mercurial.scala

 
     def command(name: String, args: String = "", options: String = "",
       repository: Boolean = true): Process_Result =
     {
       val cmdline =
-        "\"${HG:-hg}\" --config " + Bash.string("defaults." + name + "=") +
+        "export HGPLAIN=\n\"${HG:-hg}\" --config " + Bash.string("defaults." + name + "=") +
           (if (repository) " --repository " + ssh.bash_path(root) else "") +
           " --noninteractive " + name + " " + options + " " + args
       ssh.execute(cmdline)
     }