Update docs with exclude patterns

docs/DETAILS.md

@@ -34,6 +34,14 @@ types:
       - show version
       - show inventory
       - show running-config
+
+  routeros:
+    commands:
+      - system package print detail without-paging
+      - / export terse
+    exclude:
+      - "^# ....-..-.. ..:..:.. by RouterOS"    # Filter timestamp headers
+      - "^# .../../.... ..:..:.. by RouterOS"   # Alternative date format
 ```
 
 **Main configuration** (`config.yaml`):
@@ -64,6 +72,7 @@ devices:
 #### Types Section
 - **`<type-name>`**: Device type name (e.g., `srlinux`, `eos`)
   - **`commands`**: Array of CLI commands to execute
+  - **`exclude`** (optional): Array of regex patterns to filter out unwanted lines from output
 
 #### Devices Section
 - **`<hostname>`**: Device hostname (used for SSH config lookup and output filename)
@@ -85,6 +94,43 @@ ipng-router-backup --yaml "*.yaml"
 ipng-router-backup --yaml "config/*.yaml"
 ```
 
+## Output Filtering
+
+The tool supports filtering unwanted lines from command output using regular expressions in the `exclude` field of device types.
+
+### How Exclude Patterns Work
+
+- **Regex matching**: Each line of command output is tested against all exclude patterns
+- **Line removal**: Lines matching any pattern are completely removed from the output file
+- **Per-device type**: Exclude patterns are defined at the device type level and apply to all devices of that type
+
+### Common Use Cases
+
+```yaml
+types:
+  routeros:
+    commands:
+      - / export terse
+    exclude:
+      - "^# ....-..-.. ..:..:.. by RouterOS"    # Remove timestamp headers
+      - "^# .../../.... ..:..:.. by RouterOS"   # Alternative date format
+
+  cisco-ios:
+    commands:
+      - show running-config
+    exclude:
+      - "^Building configuration"               # Remove config build messages
+      - "^Current configuration"                # Remove current config headers
+      - "^!"                                   # Remove comment lines
+
+  debug-device:
+    commands:
+      - show logs
+    exclude:
+      - "^DEBUG:"                             # Filter debug messages
+      - "^TRACE:"                             # Filter trace messages
+```
+
 ## Command Line Usage
 
 ### Required Flags