docs: Add SSH BODY placeholder examples to README

- Add [BODY] placeholder to supported SSH placeholders list
- Add comprehensive examples showing various SSH BODY conditions
- Include pattern matching, length checks, JSONPath expressions
- Demonstrate function wrappers (len, has, any) usage

README.md

@@ -2951,6 +2951,57 @@ endpoints:
       - "[STATUS] == 0"
 ```
 
+You can also use the `[BODY]` placeholder to validate the command output:
+
+```yaml
+endpoints:
+  - name: ssh-body-check
+    url: "ssh://example.com:22"
+    ssh:
+      username: "username"
+      password: "password"
+    body: |
+      {
+        "command": "echo 'system is healthy'"
+      }
+    interval: 1m
+    conditions:
+      - "[CONNECTED] == true"
+      - "[STATUS] == 0"
+      - "[BODY] == system is healthy"
+      - "[BODY] == pat(*healthy*)"
+      - "len([BODY]) == 16"
+      - "has([BODY]) == true"
+      - "[BODY] != system is unhealthy"
+```
+
+For JSON output, you can use JSONPath expressions:
+
+```yaml
+endpoints:
+  - name: ssh-json-check
+    url: "ssh://example.com:22"
+    ssh:
+      username: "username"
+      password: "password"
+    body: |
+      {
+        "command": "echo '{\"status\": \"healthy\", \"memory\": {\"used\": 512, \"total\": 1024}, \"users\": [\"admin\", \"user1\"]}'"
+      }
+    interval: 1m
+    conditions:
+      - "[CONNECTED] == true"
+      - "[STATUS] == 0"
+      - "[BODY].status == healthy"
+      - "[BODY].memory.used > 500"
+      - "[BODY].memory.used < 600"
+      - "[BODY].memory.total == 1024"
+      - "len([BODY].users) == 2"
+      - "has([BODY].errors) == false"
+      - "[BODY].users[0] == admin"
+      - "[BODY].users == any(admin, user1)"
+```
+
 you can also use no authentication to monitor the endpoint by not specifying the username
 and password fields.
 
@@ -2971,6 +3022,7 @@ endpoints:
 The following placeholders are supported for endpoints of type SSH:
 - `[CONNECTED]` resolves to `true` if the SSH connection was successful, `false` otherwise
 - `[STATUS]` resolves the exit code of the command executed on the remote server (e.g. `0` for success)
+- `[BODY]` resolves to the stdout output of the command executed on the remote server
 - `[IP]` resolves to the IP address of the server
 - `[RESPONSE_TIME]` resolves to the time it took to establish the connection and execute the command