diff --git a/shell/e.cpp b/shell/e.cpp
index 337d870..ce4e31c 100644
--- a/shell/e.cpp
+++ b/shell/e.cpp
@@ -26,21 +26,21 @@ static _e_args parse_e(Session &session, Parser &parser)
 
     parser.accept_options();
 
-    VirtualSpace *space;
-    if(!args.space_name.empty())
+    VirtualSpace *space = session.current_space;
+    if(!args.space_name.empty()) {
         space = session.get_space(args.space_name);
-    else
-        space = session.current_space;
-
-    if(space)
-        while(!parser.at_end())
-            args.values.push_back(parser.expr(space));
-    else {
-        FxOS_log(ERR, "virtual space '%s' does not exist", args.space_name);
-        parser.exhaust();
+        if(!space) {
+            std::string msg =
+                format("virtual space '%s' does not exist", args.space_name);
+            if(parser.completing())
+                throw Parser::CompletionRequest("_error", msg);
+            else
+                FxOS_log(ERR, "%s", msg);
+        }
     }
 
-    // TODO: Error message when session specified in _e does not exist
+    while(!parser.at_end())
+        args.values.push_back(parser.expr(space));
 
     parser.end();
     return args;
diff --git a/shell/lexer.l b/shell/lexer.l
index 13cd7f0..1def144 100644
--- a/shell/lexer.l
+++ b/shell/lexer.l
@@ -143,7 +143,7 @@ num_suffix   [kMG]
 num          ({num_hex}|{num_dec}|{num_bin}){num_suffix}?
 
 syscall      [%][a-fA-F0-9]+
-option       [a-zA-Z]+=[^ ]+
+option       [a-zA-Z]+=[^ ]*
 symbol       [a-zA-Z_.][a-zA-Z0-9_.]*
 
 space        [ \t]+
diff --git a/shell/main.cpp b/shell/main.cpp
index 294c129..249f1b6 100644
--- a/shell/main.cpp
+++ b/shell/main.cpp
@@ -129,6 +129,11 @@ char *autocomplete(char const *text, int state)
             options = complete_region(text);
         else if(r.category == "symbol" && r.space != nullptr)
             options = complete_symbol(text, r.space);
+        else if(r.category == "_error") {
+            options.clear();
+            options.push_back("(ERROR) " + r.value);
+            options.push_back(".");
+        }
         else
             options.clear();
         i = 0;
diff --git a/shell/parser.cpp b/shell/parser.cpp
index c5f7319..cd3b264 100644
--- a/shell/parser.cpp
+++ b/shell/parser.cpp
@@ -116,6 +116,11 @@ void Parser::exhaust()
         feed();
 }
 
+bool Parser::completing() const
+{
+    return m_complete;
+}
+
 void Parser::skip_separators()
 {
     while(m_la.type == T::SEPARATOR)
@@ -319,13 +324,12 @@ long Parser::atom()
                 if(os && (int)opt->value < os->syscall_count())
                     val = os->syscall(opt->value);
             }
-            else {
-                throw CommandError("symbol '{}' is undefined", t.value.STRING);
-            }
+            else if(!m_complete)
+                FxOS_log(ERR, "symbol '%s' is undefined", t.value.STRING);
         }
-        else
-            throw CommandError(
-                "cannot query symbol '{}', no virtual space", t.value.STRING);
+        else if(!m_complete)
+            FxOS_log(ERR, "cannot query symbol '%s' (no virtual space)",
+                t.value.STRING);
         return val;
     }
     else if(t.type == T::SYSCALL) {
diff --git a/shell/parser.h b/shell/parser.h
index b77c0ba..9de9771 100644
--- a/shell/parser.h
+++ b/shell/parser.h
@@ -117,6 +117,10 @@ public:
 	void end();
 	/* Exhaust all input (usually after encountering an error) */
 	void exhaust();
+	/* Whether we are parsing for autocompletion. This is only available to
+	   allow appropriate decisions about printing vs. ignoring error messages.
+	   Do not change parsing rules based on this information! */
+	bool completing() const;
 
 	/* Expect a token of this type, or of any of the listed types */
 	Token expect(T type, bool ignore_spaces=true);