diff --git a/components/msh/msh.c b/components/msh/msh.c
index 0032c5f..b381f47 100644
--- a/components/msh/msh.c
+++ b/components/msh/msh.c
@@ -121,10 +121,7 @@ static void msh_insert_char(char c)
     }
 
     /* Check whether the cursor is at the end of the buffer */
-    if (msh.cursor == msh.bytes)
-    {
-        msh.buf[msh.bytes] = c;
-    } else
+    if (msh.cursor != msh.bytes)
     {
         /* Insert the character */
         mr_msh_printf(MSH_INSERT_CHAR(1));
@@ -134,8 +131,8 @@ static void msh_insert_char(char c)
         {
             msh.buf[i + 1] = msh.buf[i];
         }
-        msh.buf[msh.cursor] = c;
     }
+    msh.buf[msh.cursor] = c;
     msh.cursor++;
     msh.bytes++;
     msh.buf[msh.bytes] = '\0';
@@ -165,7 +162,7 @@ static int msh_parse_cmd(void)
     /* Execute the command */
     for (const struct mr_msh_cmd *msh_cmd = ((&_mr_msh_cmd_start) + 1); msh_cmd < &_mr_msh_cmd_end; msh_cmd++)
     {
-        if (strcmp(msh_cmd->name, msh.buf) != 0)
+        if (strncmp(msh_cmd->name, msh.buf, MR_CFG_MSH_NAME_MAX) != 0)
         {
             continue;
         }
@@ -356,18 +353,6 @@ static void msh_parse_key(char c)
     }
 }
 
-static void mr_msh_recv_char(char c)
-{
-    /* Judgments are characters and keys */
-    if (MSH_IS_PRINTABLE(c) && (msh.key_bytes == 0))
-    {
-        msh_insert_char(c);
-    } else
-    {
-        msh_parse_key(c);
-    }
-}
-
 static int msh_cmd_help(int argc, void *argv)
 {
     for (const struct mr_msh_cmd *msh_cmd = ((&_mr_msh_cmd_start) + 1); msh_cmd < &_mr_msh_cmd_end; msh_cmd++)
@@ -537,7 +522,14 @@ void mr_msh_handle(void)
     char c;
     while (mr_msh_input(&c) > 0)
     {
-        mr_msh_recv_char(c);
+        /* Judgments are characters and keys */
+        if (MSH_IS_PRINTABLE(c) && (msh.key_bytes == 0))
+        {
+            msh_insert_char(c);
+        } else
+        {
+            msh_parse_key(c);
+        }
     }
 }
 
diff --git a/components/msh/msh_device.c b/components/msh/msh_device.c
index 3b5013a..c98275a 100644
--- a/components/msh/msh_device.c
+++ b/components/msh/msh_device.c
@@ -147,18 +147,30 @@ static int msh_cmd_dselect(int argc, void *argv)
         goto usage;
     }
 
-    /* Parse <desc (>=0)> */
-    ret = sscanf(MR_MSH_GET_ARG(1), "%d", &desc);
-    if ((ret < 1) || (desc < 0))
+    /* Parse <-g|desc (>=0)> */
+    if (strncmp(MR_MSH_GET_ARG(1), "-g", 2) == 0)
     {
-        goto usage;
+        mr_msh_printf("%d\r\n", MSH_GET_DESC());
+        return MR_EOK;
+    } else
+    {
+        ret = sscanf(MR_MSH_GET_ARG(1), "%d", &desc);
+        if ((ret < 1) || (desc < 0))
+        {
+            goto usage;
+        }
+
+        /* Switch to the new descriptor */
+        ret = msh_update_path(desc);
+        if (ret < 0)
+        {
+            mr_msh_printf("error: %s\r\n", mr_strerror(ret));
+        }
+        return MR_EOK;
     }
 
-    /* Switch to the new descriptor */
-    return msh_update_path(desc);
-
     usage:
-    mr_msh_printf("usage: dselect <desc (>=0)>\r\n");
+    mr_msh_printf("usage: dselect <desc (>=0)|-g>\r\n");
     return MR_EINVAL;
 }
 
@@ -669,7 +681,7 @@ static int msh_cmd_dread(int argc, void *argv)
     }
 
     /* Read data */
-    size = MR_BOUND(size *itemsz, 0, sizeof(buf));
+    size = MR_BOUND(size * itemsz, 0, sizeof(buf));
     ret = (int)mr_dev_read(MSH_GET_DESC(), buf, size);
     if (ret < 0)
     {