diff --git a/dangerzone/cli.py b/dangerzone/cli.py
index 7265bc9..2b6b385 100644
--- a/dangerzone/cli.py
+++ b/dangerzone/cli.py
@@ -1,8 +1,63 @@
 import click
 
+from .global_common import GlobalCommon
+
+
+def exec_container(global_common, args):
+    output = ""
+
+    with global_common.exec_dangerzone_container(args) as p:
+        for line in p.stdout:
+            output += line.decode()
+            print(line.decode(), end="")
+
+        stderr = p.stderr.read().decode()
+        print(stderr)
+
+    if p.returncode == 126 or p.returncode == 127:
+        click.echo(f"Authorization failed")
+    elif p.returncode == 0:
+        click.echo(f"Return code: {p.returncode}")
+
+    print("")
+    return p.returncode, output, stderr
+
 
 @click.command()
-@click.option("--custom-container")  # Use this container instead of flmcode/dangerzone
-@click.argument("filename", required=False)
-def cli_main(custom_container, filename):
-    pass
+@click.option("--custom-container", help="Use a custom container")
+@click.option("--safe-pdf-filename", help="Default is filename ending with -safe.pdf")
+@click.option("--ocr-lang", help="Language to OCR, defaults to none")
+@click.option(
+    "--skip-update",
+    is_flag=True,
+    help="Don't update flmcode/dangerzone container",
+)
+@click.argument("filename", required=True)
+def cli_main(custom_container, safe_pdf_filename, ocr_lang, skip_update, filename):
+    global_common = GlobalCommon()
+
+    # Make sure custom container exists
+    if custom_container:
+        success, error_message = global_common.container_exists(custom_container)
+        if not success:
+            click.echo(error_message)
+            return
+
+        global_common.custom_container = custom_container
+    else:
+        if skip_update:
+            # Make sure flmcode/dangerzone exists
+            success, error_message = global_common.container_exists(
+                "flmcode/dangerzone"
+            )
+            if not success:
+                click.echo(
+                    "You don't have the flmcode/dangerzone container so you can't use --skip-update"
+                )
+                return
+
+    if not skip_update:
+        click.echo("Pulling container image (this might take a few minutes)")
+        returncode, _, _ = exec_container(global_common, ["pull"])
+        if returncode != 0:
+            return
diff --git a/dangerzone/global_common.py b/dangerzone/global_common.py
index 084e79f..ef0440c 100644
--- a/dangerzone/global_common.py
+++ b/dangerzone/global_common.py
@@ -274,3 +274,26 @@ class GlobalCommon(object):
             return startupinfo
         else:
             return None
+
+    def container_exists(self, container_name):
+        # Do we have this container?
+        with self.exec_dangerzone_container(
+            ["ls", "--container-name", container_name]
+        ) as p:
+            stdout_data, _ = p.communicate()
+            if stdout_data.startswith(b"Executing: "):
+                stdout_data = b"\n".join(stdout_data.split(b"\n")[1:])
+
+            # The user canceled, or permission denied
+            if p.returncode == 126 or p.returncode == 127:
+                return False, "Authorization failed"
+                return
+            elif p.returncode != 0:
+                return False, "Container error"
+                return
+
+            # Check the output
+            if container_name.encode() not in stdout_data:
+                return False, f"Container '{container_name}' not found"
+
+        return True, True
diff --git a/dangerzone/gui/__init__.py b/dangerzone/gui/__init__.py
index a2c59a8..65ccddd 100644
--- a/dangerzone/gui/__init__.py
+++ b/dangerzone/gui/__init__.py
@@ -15,7 +15,6 @@ from .docker_installer import (
     AuthorizationFailed,
 )
 from ..global_common import GlobalCommon
-from ..container import container_runtime
 
 
 # For some reason, Dangerzone segfaults if I inherit from QApplication directly, so instead
@@ -62,24 +61,10 @@ def gui_main(custom_container, filename):
     gui_common = GuiCommon(app, global_common)
 
     if custom_container:
-        # Do we have this container?
-        with global_common.exec_dangerzone_container(
-            ["ls", "--container-name", custom_container]
-        ) as p:
-            stdout_data, stderr_data = p.communicate()
-
-            # The user canceled, or permission denied
-            if p.returncode == 126 or p.returncode == 127:
-                click.echo("Authorization failed")
-                return
-            elif p.returncode != 0:
-                click.echo("Container error")
-                return
-
-            # Check the output
-            if custom_container.encode() not in stdout_data:
-                click.echo(f"Container '{custom_container}' not found")
-                return
+        success, error_message = global_common.container_exists(custom_container)
+        if not success:
+            click.echo(error_message)
+            return
 
         global_common.custom_container = custom_container
 
diff --git a/dangerzone/tasks.py b/dangerzone/gui/tasks.py
similarity index 100%
rename from dangerzone/tasks.py
rename to dangerzone/gui/tasks.py
diff --git a/dangerzone/gui/tasks_widget.py b/dangerzone/gui/tasks_widget.py
index ab77f47..94a00a4 100644
--- a/dangerzone/gui/tasks_widget.py
+++ b/dangerzone/gui/tasks_widget.py
@@ -5,7 +5,7 @@ import platform
 import subprocess
 from PySide2 import QtCore, QtGui, QtWidgets
 
-from ..tasks import PullImageTask, ConvertToPixels, ConvertToPDF
+from .tasks import PullImageTask, ConvertToPixels, ConvertToPDF
 
 
 class TasksWidget(QtWidgets.QWidget):