diff --git a/morel b/morel
index 700a7fd1..9bc330dc 100755
--- a/morel
+++ b/morel
@@ -52,6 +52,9 @@ fi
 
 export JAVA_OPTS=-Djavax.xml.parsers.DocumentBuilderFactory=com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl
 
-exec java $VM_OPTS -cp "${CP}" $JAVA_OPTS net.hydromatic.morel.Shell --foreign='net.hydromatic.morel.BuiltInDataSet$Dictionary' "$@"
+exec java $VM_OPTS -cp "${CP}" $JAVA_OPTS net.hydromatic.morel.Shell \
+     --foreign='net.hydromatic.morel.BuiltInDataSet$Dictionary' \
+     --directory="$(pwd)" \
+     "$@"
 
 # End morel
diff --git a/src/main/java/net/hydromatic/morel/Main.java b/src/main/java/net/hydromatic/morel/Main.java
index 7a7a2c89..f5db7439 100644
--- a/src/main/java/net/hydromatic/morel/Main.java
+++ b/src/main/java/net/hydromatic/morel/Main.java
@@ -27,6 +27,7 @@
 import net.hydromatic.morel.compile.Tracer;
 import net.hydromatic.morel.compile.Tracers;
 import net.hydromatic.morel.eval.Codes;
+import net.hydromatic.morel.eval.Prop;
 import net.hydromatic.morel.eval.Session;
 import net.hydromatic.morel.foreign.ForeignValue;
 import net.hydromatic.morel.parse.MorelParserImpl;
@@ -69,9 +70,8 @@ public class Main {
   private final boolean echo;
   private final Map<String, ForeignValue> valueMap;
   final TypeSystem typeSystem = new TypeSystem();
-  final File directory;
   final boolean idempotent;
-  final Session session = new Session();
+  final Session session;
 
   /** Command-line entry point.
    *
@@ -102,7 +102,9 @@ public Main(List<String> argList, Reader in, Writer out,
     this.out = buffer(out);
     this.echo = argList.contains("--echo");
     this.valueMap = ImmutableMap.copyOf(valueMap);
-    this.directory = requireNonNull(directory, "directory");
+    final Map<Prop, Object> map = new LinkedHashMap<>();
+    Prop.DIRECTORY.set(map, requireNonNull(directory, "directory"));
+    this.session = new Session(map);
     this.idempotent = idempotent;
   }
 
@@ -311,7 +313,8 @@ static class SubShell extends Shell {
       outLines.accept("[opening " + fileName + "]");
       File file = new File(fileName);
       if (!file.isAbsolute()) {
-        file = new File(main.directory, fileName);
+        final File directory = Prop.DIRECTORY.fileValue(main.session.map);
+        file = new File(directory, fileName);
       }
       if (!file.exists()) {
         outLines.accept("[use failed: Io: openIn failed on "
diff --git a/src/main/java/net/hydromatic/morel/Shell.java b/src/main/java/net/hydromatic/morel/Shell.java
index b95f9e13..505e86d6 100644
--- a/src/main/java/net/hydromatic/morel/Shell.java
+++ b/src/main/java/net/hydromatic/morel/Shell.java
@@ -28,6 +28,7 @@
 import net.hydromatic.morel.compile.Tracer;
 import net.hydromatic.morel.compile.Tracers;
 import net.hydromatic.morel.eval.Codes;
+import net.hydromatic.morel.eval.Prop;
 import net.hydromatic.morel.eval.Session;
 import net.hydromatic.morel.foreign.Calcite;
 import net.hydromatic.morel.foreign.DataSet;
@@ -259,8 +260,10 @@ public void run() {
 
     pause();
     final TypeSystem typeSystem = new TypeSystem();
+    final Map<Prop, Object> map = new LinkedHashMap<>();
+    Prop.DIRECTORY.set(map, config.directory);
+    final Session session = new Session(map);
     Environment env = Environments.env(typeSystem, config.valueMap);
-    final Session session = new Session();
     final LineFn lineFn =
         new TerminalLineFn(minusPrompt, equalsPrompt, lineReader);
     final SubShell subShell =
diff --git a/src/main/java/net/hydromatic/morel/compile/CalciteCompiler.java b/src/main/java/net/hydromatic/morel/compile/CalciteCompiler.java
index 52abea95..6a30e9b3 100644
--- a/src/main/java/net/hydromatic/morel/compile/CalciteCompiler.java
+++ b/src/main/java/net/hydromatic/morel/compile/CalciteCompiler.java
@@ -176,7 +176,7 @@ Code toRel4(Environment env, Code code, Type type) {
 
   @Override protected CalciteFunctions.Context createContext(
       Environment env) {
-    final Session dummySession = new Session();
+    final Session dummySession = new Session(ImmutableMap.of());
     return new CalciteFunctions.Context(dummySession, env, typeSystem,
         calcite.dataContext.getTypeFactory());
   }
@@ -308,7 +308,7 @@ Code toRel4(Environment env, Code code, Type type) {
                 new RelJson(jsonBuilder).toJson(rowType));
         final String morelCode = apply.toString();
         ThreadLocals.let(CalciteFunctions.THREAD_ENV,
-            new CalciteFunctions.Context(new Session(), cx.env,
+            new CalciteFunctions.Context(new Session(ImmutableMap.of()), cx.env,
                 typeSystem, cx.relBuilder.getTypeFactory()), () ->
             cx.relBuilder.functionScan(CalciteFunctions.TABLE_OPERATOR, 0,
                 cx.relBuilder.literal(morelCode),
diff --git a/src/main/java/net/hydromatic/morel/compile/Compiler.java b/src/main/java/net/hydromatic/morel/compile/Compiler.java
index 89d885b5..3f1ae2f0 100644
--- a/src/main/java/net/hydromatic/morel/compile/Compiler.java
+++ b/src/main/java/net/hydromatic/morel/compile/Compiler.java
@@ -47,6 +47,7 @@
 import net.hydromatic.morel.util.ThreadLocals;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSortedMap;
 import org.apache.calcite.util.Util;
@@ -133,7 +134,7 @@ public void eval(Session session, Environment env,
    * not created a session yet. Lifecycle confusion.
    * </ul> */
   protected CalciteFunctions.Context createContext(Environment env) {
-    final Session dummySession = new Session();
+    final Session dummySession = new Session(ImmutableMap.of());
     return new CalciteFunctions.Context(dummySession, env, typeSystem, null);
   }
 
diff --git a/src/main/java/net/hydromatic/morel/eval/Prop.java b/src/main/java/net/hydromatic/morel/eval/Prop.java
index f2f87151..c0d0ff1b 100644
--- a/src/main/java/net/hydromatic/morel/eval/Prop.java
+++ b/src/main/java/net/hydromatic/morel/eval/Prop.java
@@ -21,6 +21,7 @@
 import com.google.common.base.CaseFormat;
 import com.google.common.collect.ImmutableMap;
 
+import java.io.File;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
@@ -29,6 +30,15 @@
  * @see Session#map
  */
 public enum Prop {
+  /** File property "directory" is the path of the directory that the
+   * {@code file} variable maps to in this connection.
+   *
+   * <p>The default value is the empty string;
+   * many tests use the "src/test/resources" directory;
+   * when launched via the {@code morel} shell script, the default value is the
+   * shell's current directory. */
+  DIRECTORY("directory", File.class, new File("")),
+
   /** Boolean property "hybrid" controls whether to try to create a hybrid
    * execution plan that uses Apache Calcite relational algebra wherever
    * possible. Default is false. */
@@ -114,6 +124,10 @@ public enum Prop {
       assert defaultValue == null || defaultValue.getClass() == type;
     } else if (type == Integer.class) {
       assert defaultValue == null || defaultValue.getClass() == type;
+    } else if (type == String.class) {
+      assert defaultValue == null || defaultValue.getClass() == type;
+    } else if (type == File.class) {
+      assert defaultValue == null || defaultValue.getClass() == type;
     } else {
       throw new AssertionError("not a valid property type: "
           + type);
@@ -149,6 +163,20 @@ public int intValue(Map<Prop, Object> map) {
     return this.<Integer>typeValue(o);
   }
 
+  /** Returns the value of a string property. */
+  public String stringValue(Map<Prop, Object> map) {
+    assert type == String.class;
+    Object o = map.get(this);
+    return this.typeValue(o);
+  }
+
+  /** Returns the value of a file property. */
+  public File fileValue(Map<Prop, Object> map) {
+    assert type == File.class;
+    Object o = map.get(this);
+    return this.typeValue(o);
+  }
+
   @SuppressWarnings("unchecked")
   private <T> T typeValue(Object o) {
     if (o == null) {
diff --git a/src/main/java/net/hydromatic/morel/eval/Session.java b/src/main/java/net/hydromatic/morel/eval/Session.java
index 7f0d84bf..7e327596 100644
--- a/src/main/java/net/hydromatic/morel/eval/Session.java
+++ b/src/main/java/net/hydromatic/morel/eval/Session.java
@@ -39,11 +39,23 @@ public class Session {
   /** The output lines of the previous command. */
   public List<String> out;
   /** Property values. */
-  public final Map<Prop, Object> map = new LinkedHashMap<>();
+  public final Map<Prop, Object> map;
 
   /** Implementation of "use". */
   private Shell shell = Shells.INSTANCE;
 
+  /** Creates a Session.
+   *
+   * <p>The {@code map} parameter, that becomes the property map, is used as is,
+   * not copied. It may be immutable if the session is for a narrow, internal
+   * use. Otherwise, it should probably be a {@link LinkedHashMap} to provide
+   * deterministic iteration order.
+   *
+   * @param map Map that contains property values */
+  public Session(Map<Prop, Object> map) {
+    this.map = map;
+  }
+
   /** Calls some code with a new value of {@link Shell}. */
   public void withShell(Shell shell, Consumer<String> outLines,
       Consumer<Session> consumer) {
diff --git a/src/test/java/net/hydromatic/morel/Ml.java b/src/test/java/net/hydromatic/morel/Ml.java
index 8d2e1ff2..f052d55b 100644
--- a/src/test/java/net/hydromatic/morel/Ml.java
+++ b/src/test/java/net/hydromatic/morel/Ml.java
@@ -267,7 +267,7 @@ Ml withPrepare(Consumer<CompiledStatement> action) {
         final TypeSystem typeSystem = new TypeSystem();
         final AstNode statement = parser.statementEof();
         final Environment env = Environments.empty();
-        final Session session = new Session();
+        final Session session = new Session(propMap);
         final List<CompileException> warningList = new ArrayList<>();
         final CompiledStatement compiled =
             Compiles.prepareStatement(typeSystem, session, env, statement,
@@ -428,8 +428,7 @@ Ml assertEval(Matcher<Object> resultMatcher) {
 
   Ml assertEval() {
     return withValidate((resolved, calcite) -> {
-      final Session session = new Session();
-      session.map.putAll(propMap);
+      final Session session = new Session(propMap);
       eval(session, resolved.env, resolved.typeMap.typeSystem, resolved.node,
           calcite);
     });