refer to mamba activate for activation hint

mamba/mamba/mamba.py

@@ -19,7 +19,7 @@
     ensure_name_or_prefix,
     specs_from_url,
 )
-from conda.cli.install import check_prefix, clone, get_revision, print_activate
+from conda.cli.install import check_prefix, clone, get_revision
 from conda.cli.main import generate_parser, init_loggers
 from conda.common.compat import on_win
 from conda.common.path import paths_equal
@@ -50,7 +50,13 @@
 from mamba import repoquery as repoquery_api
 from mamba.linking import handle_txn
 from mamba.mamba_shell_init import shell_init
-from mamba.utils import get_installed_jsonfile, init_api_context, load_channels, to_txn
+from mamba.utils import (
+    get_installed_jsonfile,
+    init_api_context,
+    load_channels,
+    print_activate,
+    to_txn,
+)
 
 if sys.version_info < (3, 2):
     sys.stdout = codecs.lookup("utf-8")[-1](sys.stdout)
@@ -898,10 +904,8 @@ def main(*args, **kwargs):
 
     if "activate" in sys.argv or "deactivate" in sys.argv:
         print(
-            f"Run 'mamba init' to be able to run mamba activate/deactivate\n"
-            f"and start a new shell session. Or use conda to activate/deactivate.\n"
-            f"\n"
-            f"    $ conda {' '.join(sys.argv[1:])}\n",
+            "Run 'mamba init' to be able to run mamba activate/deactivate\n"
+            "and start a new shell session. Or use conda to activate/deactivate.\n",
             file=sys.stderr,
         )
         return sys.exit(-1)

mamba/mamba/utils.py

@@ -430,3 +430,14 @@ def to_txn(
         prefix,
         final_precs,
     )
+
+
+def print_activate(env_name_or_prefix):  # pragma: no cover
+    if not context.quiet and not context.json:
+        message = (
+            "\nTo activate this environment, use\n\n"
+            f"     $ mamba activate {env_name_or_prefix}\n\n"
+            "To deactivate an active environment, use\n\n"
+            "     $ mamba deactivate\n"
+        )
+        print(message)  # TODO: use logger