If you connect to newer Cisco devices (like Nexus switches or IOS-XE) that output colors automatically, ensure Xshell is not stripping them:
Pro Tip: If you want to highlight configuration lines that are simply "active" (not negated), use the regex ^[^ !no].* to match lines that do not start with a space, exclamation mark, or the word "no". This effectively highlights active configuration commands.
Xshell Highlight Sets for Cisco devices allow you to visually distinguish critical commands, interface statuses, and configuration errors in real-time, significantly reducing human error during network troubleshooting. By defining specific colors for keywords like "UP," "DOWN," or "err-disable," network engineers can parse dense CLI outputs at a glance. How to Configure Cisco Highlight Sets in Xshell
Setting up a custom highlight set in Xshell is a straightforward process accessible through the Tools menu.
Access the Dialog: Navigate to Tools > Terminal Highlight Sets.
Create New Set: Click New, name your set (e.g., "Cisco_Highlighter"), and click OK. Add Keywords: Click Add to enter specific words or regular expressions. xshell highlight sets cisco
Example: Use \bDOWN\b to highlight the word "DOWN" only when it appears as a whole word.
Assign a color (e.g., bright red) and font style (e.g., bold) to the keyword. Apply to Sessions:
Current Session: In the Highlight Sets dialog, select your set and click Set to Current.
Permanently: Open Session Properties > Appearance and select your "Cisco" set from the Highlight Set dropdown menu. Recommended Highlight Patterns for Cisco IOS
The following patterns are commonly used by network engineers to improve CLI readability: Recommended Keyword/Regex Color Suggestion Status: Up up, established, connected Emerald Green Status: Down down, shutdown, administratively down Bright Red Errors err-disable, error, CRC, collision Bold Red or Orange IP Addresses \b(?:[0-9]1,3\.)3[0-9]1,3\b Cyan or Light Blue Interfaces (Gi|Fa|Te|Et)[0-9]/[0-9]+ User/Auth password, secret, username Advanced Tips for Networking Pros If you connect to newer Cisco devices (like
Use Regex Engines: Xshell utilizes the Perl-compatible DEELX engine. Ensure you check the Regular Expression box when adding complex patterns like MAC or IP addresses to ensure they match correctly.
Avoid "Christmas Tree" CLI: Too many colors can be distracting. Stick to a dark background (like the "Jellybeans" scheme) with high-visibility neon colors reserved strictly for status indicators and errors.
Team Sharing: You can export your highlight sets to share with colleagues, ensuring your entire engineering team uses the same visual standard for troubleshooting.
Terminal Type Sensitivity: If colors do not appear, ensure your terminal type is set to xterm or vt320 in the session properties.
Purpose: Instantly see which ports are down.
| Description | Regex Pattern | Color |
| :--- | :--- | :--- |
| Protocol Down | (line protocol is down) | Red, Bold |
| Admin Down | (administratively down) | Yellow, Bold |
| Physical Down | FastEthernet.* is down, line | Red |
| Physical Up | GigabitEthernet.* is up, line | Green, Bold | Pro Tip: If you want to highlight configuration
Pro Tip: Use Non-capturing groups (?:...) for performance:
(?:line protocol is down|administratively down)
| Pattern | Matches | Suggested color |
|---------|---------|----------------|
| \b([0-9]1,3\.)3[0-9]1,3\b | IPv4 address | Green |
| \b([A-Fa-f0-9]4\.)2[A-Fa-f0-9]4\b | MAC address | Purple |
| (Gi|Fa|Te|Et)[0-9]/[0-9]+ | Interface names (Gi1/0) | Yellow |
| (Down|down|disabled) | Port down state | Red |
| (Up\|up\|up/up) | Port up state | Green |
| (error\|failed\|denied\|invalid) | Error keywords | Red background |
| \b[0-9]+\.[0-9]+\.[0-9]+\b | Cisco IOS version | Cyan |
| %[A-Z]+-[0-9] | Syslog message ID | Orange |
⚠️ Xshell uses ECMAScript (JavaScript) regex. Backslashes need escaping in the UI.
Xshell processes highlights from top to bottom. If you have a general rule (e.g., "IP Address" = Blue) and a specific rule ("10.0.0.1" = Red), the specific rule must come above the general rule. Use the Move Up/Move Down buttons.
If every line is a different neon color, you've defeated the purpose. Stick to 3-4 critical colors. Reserve bright red for actual outages, not for the word "interface."
In Xshell, when you check "Match whole word only", it automatically wraps your keyword in regex boundaries. For simple words like "down", use this checkbox instead of writing \bdown\b.
In the Options window, look for the Highlight tab or section. This is where you can configure what gets highlighted and how.
