diff --git a/src/exec/rust-toolchain b/src/exec/rust-toolchain
deleted file mode 100644
index 4e74872f..00000000
--- a/src/exec/rust-toolchain
+++ /dev/null
@@ -1 +0,0 @@
-nightly-2020-04-07
diff --git a/src/exec/src/lib.rs b/src/exec/src/lib.rs
index 45cddfe6..ecc57b3e 100644
--- a/src/exec/src/lib.rs
+++ b/src/exec/src/lib.rs
@@ -5,8 +5,12 @@ extern crate protobuf;
 #[macro_use]
 extern crate log;
 
+// Skip formatting the two modules because they are generated by grpc framework.
+#[rustfmt::skip]
 pub mod occlum_exec;
+#[rustfmt::skip]
 pub mod occlum_exec_grpc;
+
 pub mod server;
 
 pub const DEFAULT_SERVER_FILE: &'static str = "occlum_exec_server";
diff --git a/src/sgxenv.mk b/src/sgxenv.mk
index 82dba609..28fa568e 100644
--- a/src/sgxenv.mk
+++ b/src/sgxenv.mk
@@ -3,6 +3,8 @@ INCLUDE_MAKEFILE := $(lastword $(MAKEFILE_LIST))
 CUR_DIR := $(shell dirname $(realpath $(MAIN_MAKEFILE)))
 PROJECT_DIR := $(realpath $(CUR_DIR)/../../)
 
+SHELL := /bin/bash
+
 SGX_SDK ?= /opt/intel/sgxsdk
 SGX_MODE ?= HW
 SGX_ARCH ?= x64
@@ -140,14 +142,17 @@ SGX_LFLAGS_T = $(SGX_COMMON_CFLAGS) -nostdlib -L$(SGX_LIBRARY_PATH) $(_Other_Lin
 define format-rust
 	output=$$(cargo fmt -- --check 2>&1); retval=$$?; \
 		if [[ $$retval -eq 1 ]]; then \
-			$(ECHO) "$$output"; cargo fmt; $(ECHO) "$(GREEN)\nRust code format corrected.$(NO_COLOR)"; \
+			$(ECHO) "$$output"; \
+			cargo fmt; \
+			$(ECHO) "$(GREEN)\nRust code format corrected.$(NO_COLOR)"; \
 		fi
 endef
 
 define format-check-rust
 	output=$$(cargo fmt -- --check 2>&1); retval=$$?; \
 		if [[ $$retval -eq 1 ]]; then \
-			$(ECHO) "$(RED)\nSome format issues of Rust code are detected:$(NO_COLOR)"; $(ECHO) "\n$$output"; \
+			$(ECHO) "$(RED)\nSome format issues of Rust code are detected:$(NO_COLOR)"; \
+			$(ECHO) "\n$$output"; \
 			$(ECHO) "\nTo get rid of the format warnings above, run $(CYAN)"make format"$(NO_COLOR) to correct"; \
 		fi
 endef