🔧 Advanced Theme Customization Guide

Introduction
Theme Structure Deep Dive
Segment Customization
Template Expressions
Custom Icons & Symbols
Color Manipulation
Advanced Block Layouts
Creating Custom Segments
Performance Tuning
Best Practices

Introduction

While the OhMyPosh Atomic Enhanced themes come pre-configured and visually complete, true mastery requires understanding how to modify and extend them. This guide covers advanced customization techniques that go beyond changing color palettes.

What You’ll Learn

Modifying existing segments for different information
Writing complex template expressions
Creating entirely new segments
Optimizing themes for your specific workflow
Integrating custom scripts and commands

Theme Structure Deep Dive

JSON Schema Overview

Every Oh My Posh theme follows a defined JSON schema. Understanding this structure is essential for modifications.

{
 "$schema": "https://raw.githubusercontent.com/JanDeDobbeleer/oh-my-posh/main/themes/schema.json",
 "accent_color": "#00bcd4",
 "blocks": [
  // Prompt layout blocks
 ],
 "console_title": "{{ .Shell }} - {{.Folder}}",
 "console_title_template": "{{.Folder}}",
 "final_space": true,
 "palette": {
  // Color definitions
 },
 "tooltip": {
  "text": "{{.Name}}",
  "background": "transparent",
  "foreground": "#000000"
 },
 "transient_prompt": {
  // Optional simplified prompt after execution
 },
 "version": 3
}

Key Top-Level Properties

Property	Purpose	Example
`$schema`	Validation & IDE support	Official schema URL
`version`	Schema version for Oh My Posh	`3` (current)
`final_space`	Trailing space in prompt	`true` or `false`
`console_title_template`	Terminal tab/window title	`"{{.Folder}}"`
`accent_color`	Primary accent hue (not palette)	`"#00bcd4"`
`palette`	Color definitions object	`{...}`
`blocks`	Array of prompt line blocks	`[{...}]`
`transient_prompt`	Quick re-prompt display	Optional `{...}`

Block Structure

{
 "alignment": "left|right|rprompt|newline",
 "segments": [
  {
   "type": "segment_type",
   "background": "p:palette_key|#hexcolor",
   "foreground": "p:palette_key|#hexcolor",
   "template": "template_string",
   "properties": {},
   "style": "powerline|diamond|plain",
   "leading_diamond": "◊",
   "trailing_diamond": "◊",
   "cache": {
    "strategy": "session|folder|windows",
    "duration": "5m",
    "skip_cache": false
   }
  }
 ],
 "vertical_offset": 0
}

Segment Customization

Common Segment Types

Oh My Posh provides numerous built-in segment types. Each type accepts different properties and templates.

Path Segment

Displays the current working directory with customizable format.

{
 "background": "p:blue_primary",
 "foreground": "p:white",
 "properties": {
  "style": "folder",
  "max_depth": 3,
  "folder_separator_icon": "/",
  "home_icon": "~",
  "hide_root_location": false,
  "read_only_icon": "🔒",
  "truncation_mode": "start",
  "truncated_indicator": "....",
  "mapped_locations": {
   "C:\\Users\\YourName\\Documents": "📄 Docs",
   "C:\\Users\\YourName\\Desktop": "🖥️ Desktop",
   "/home/user/projects": "💼 Projects"
  }
 },
 "style": "powerline",
 "template": " {{ .Path }} ",
 "type": "path"
}

Customization Options:

{
 "properties": {
  "style": "mixed|folder|letter",
  "max_depth": 2,
  "folder_separator_icon": " > ",
  "home_icon": "⌂",
  "read_only_icon": "  ",
  "truncation_mode": "start|end|middle",
  "truncated_indicator": "…",
  "mapped_locations": {
   "/home/user/dev": "🔧 Dev",
   "C:\\code": "📝 Code"
  }
 }
}

Git Segment

Shows git status with detailed information.

{
 "background": "p:yellow_bright",
 "foreground": "p:black",
 "properties": {
  "fetch_status": true,
  "fetch_upstream_icon": true,
  "branch_max_length": 25,
  "truncation_symbol": "…",
  "fetch_worktree_count": false,
  "windows_registry": false
 },
 "style": "powerline",
 "template": " {{ .Branch }} ",
 "type": "git"
}

Advanced Git Template:

{
 "template": "{{ if .UpstreamIcon }}{{ .UpstreamIcon }} {{ end }}{{ .Branch }}{{ if .BranchStatus }} {{ .BranchStatus }}{{ end }}{{ if .RepositoryStatus }} {{ .RepositoryStatus }}{{ end }}"
}

Status Segment

Indicates success/failure of last command.

{
 "background": "p:green_success",
 "background_templates": [
  "{{ if .Error }}p:maroon_error{{ else }}p:green_success{{ end }}"
 ],
 "foreground": "p:black",
 "leading_diamond": "◊",
 "style": "diamond",
 "template": " {{ if .Error }}✗{{ else }}✓{{ end }} ",
 "trailing_diamond": "◊",
 "type": "status"
}

Custom Shell Variables Segment

Display any environment variable or command output.

{
 "background": "p:blue_primary",
 "cache": {
  "strategy": "session",
  "duration": "1h"
 },
 "foreground": "p:white",
 "properties": {
  "var_name": "CUSTOM_VAR"
 },
 "template": " {{ .Env.CUSTOM_VAR }} ",
 "type": "env"
}

Command Segment (Advanced)

Execute custom commands and display results.

{
 "background": "p:purple_session",
 "cache": {
  "strategy": "session",
  "duration": "2s"
 },
 "foreground": "p:white",
 "properties": {
  "shell": "powershell",
  "command": "Get-Date -Format 'HH:mm:ss'",
  "parse": true,
  "parse_separator": ":"
 },
 "template": "{{ .Output }}",
 "type": "command"
}

Language Version Segments

Display runtime versions for Node, Python, etc.

{
 "background": "p:node_green",
 "cache": {
  "strategy": "folder",
  "duration": "5m"
 },
 "foreground": "p:black",
 "properties": {
  "fetch_version": true
 },
 "style": "powerline",
 "template": " ⬢ {{ .Full }} ",
 "type": "node"
}

Template Expressions

Basics

Oh My Posh uses Go template syntax (similar to Handlebars). Templates appear in the template property and background_templates array.

Simple Variable Substitution

{
 "template": "User: {{ .User }}" // Output: User: john
}

Conditional Logic

{
 "template": "{{ if .Error }}✗ Failed{{ else }}✓ Success{{ end }}"
}

Loops (Arrays)

{
 "template": "{{ range .Items }}{{ . }}{{ end }}"
}

Advanced Template Patterns

Multi-Part Templates with Fallbacks

{
 "template": "{{ if .Version }}{{ .Name }} {{ .Version }}{{ else }}{{ .Name }}{{ end }}"
}

Color Blending in Templates

{
 "template": "<#00bcd4>Cyan</>{{ .Content }}<#ff0000>Red</>"
}

Complex Conditional State

{
 "template": "{{ if or .Error .Detached }}{{ if .Detached }}(detached){{ else }}(error){{ end }}{{ else }}{{ .Branch }}{{ end }}",
 "type": "git"
}

Conditional Spacing

{
 "template": "{{ if .Value }} {{ .Value }} {{ else }}(empty){{ end }}"
}

Background Based on Condition

{
 "background_templates": [
  "{{ if eq .ExitCode 0 }}p:green_success{{ else }}p:red_alert{{ end }}"
 ]
}

Built-In Template Functions

Function	Purpose	Example
`eq`	Equals comparison	`{{ if eq .Shell "pwsh" }}PowerShell{{ end }}`
`ne`	Not equals	`{{ if ne .User "root" }}Regular User{{ end }}`
`gt`	Greater than	`{{ if gt .Memory 80 }}High Memory{{ end }}`
`lt`	Less than	`{{ if lt .Memory 20 }}Low Memory{{ end }}`
`and`	Logical AND	`{{ if and .Error .Warning }}Both{{ end }}`
`or`	Logical OR	`{{ if or .Error .Warning }}Either{{ end }}`
`not`	Logical NOT	`{{ if not .Error }}Success{{ end }}`
`len`	Length of string	`{{ if gt (len .Text) 5 }}Long{{ end }}`
`contains`	String contains	`{{ if contains .Path "node_modules" }}Has deps{{ end }}`
`split`	Split string	`{{ index (split .Path "/") 0 }}`
`join`	Join array	`{{ join (split .Path "/") "-" }}`
`title`	Capitalize	`{{ title .Name }}`
`lower`	Lowercase	`{{ lower .Text }}`
`upper`	Uppercase	`{{ upper .Text }}`

Practical Template Examples

Status Segment with Icons

{
 "template": "{{ if .Error }}❌ {{ .Error.Message }}{{ else }}✅{{ end }}",
 "type": "status"
}

Git with Upstream Status

{
 "template": "{{ if .UpstreamIcon }}{{ .UpstreamIcon }} {{ end }}{{ .Branch }}{{ if .BranchStatus }} ({{ .BranchStatus }}){{ end }}",
 "type": "git"
}

Path with Dynamic Truncation

{
 "template": "{{ if gt (len .Path) 40 }}...{{ substr .Path -35 }}{{ else }}{{ .Path }}{{ end }}",
 "type": "path"
}

Environment Indicator

{
 "properties": {
  "var_name": "ENVIRONMENT"
 },
 "template": "{{ if .Env.DEVELOPMENT }}[DEV]{{ else if .Env.STAGING }}[STAGING]{{ else }}[PROD]{{ end }}",
 "type": "env"
}

Custom Icons & Symbols

Icon Strategy

Icons add visual richness to prompts while reducing text verbosity.

Built-in Icon Libraries

Oh My Posh includes collections of pre-designed icons:

Powerline symbols: ` `
Nerd Font icons: Various glyphs
Unicode symbols: ✓ ✗ ◆ ⬢ ⬡

Using Icons in Templates

{
 "template": "⎇ {{ .Branch }}",
 "type": "git"
}

Conditional Icons Based on State

{
 "template": "{{ if .Error }}󰅖 Error{{ else }}󰄬 Success{{ end }}",
 "type": "status"
}

Custom Icon Mapping

{
 "template": "{{ if contains .Output 'python' }}🐍 Python{{ else if contains .Output 'node' }}⬢ Node{{ else }}?{{ end }}",
 "type": "command"
}

Nerd Font Resources

Use sites like nerdfonts.com to browse available icons:

DevIcons (dev tools)
Font Awesome
Material Design Icons
Powerline Symbols

Example Icons

Icon	Unicode	Name	Use Case
⬢	U+2B22	Node.js	JavaScript/TypeScript
🐍	U+1F40D	Python	Python projects
󰌠	Custom	Rust	Rust projects
☸	U+2328	Kubernetes	K8s contexts
󰔒	Custom	Lock	Read-only indicator
⚡	U+26A1	Electricity	Power/speed indicator
🔧	U+1F527	Wrench	Tools/configuration
📦	U+1F4E6	Package	Dependencies

Color Manipulation

Using the Palette System

The palette centralizes all color definitions, enabling easy theme swaps.

Palette Entry Reference Format

p:<palette_key>

Example References

{
 "background": "p:blue_primary",
 "foreground": "p:white"
}

Defining Custom Palette Entries

{
 "palette": {
  "my_custom_color": "#FF6B9D",
  "my_custom_dark": "#2D1B3D",
  "my_accent": "#00D9FF"
 }
}

Hex Color References

When not using palettes, you can specify colors directly:

{
 "background": "#000000",
 "foreground": "#FFFFFF"
}

Dynamic Colors Based on Conditions

The background_templates array allows conditional colors:

{
 "background_templates": [
  "{{ if .Error }}p:red_alert{{ else }}p:green_success{{ end }}"
 ],
 "foreground": "p:white",
 "template": "{{ if .Error }}✗{{ else }}✓{{ end }}",
 "type": "status"
}

Color Blending Techniques

While Oh My Posh doesn’t directly support color blending, you can simulate it by:

Using intermediate colors in palette
Conditional color selection based on context
Using divider segments with blend colors

{
 "palette": {
  "red_to_orange": "#FF4500",
  "orange_to_yellow": "#FFB347",
  "yellow_to_green": "#ADFF2F"
 }
}

Advanced Block Layouts

Block Alignment Options

{
 "alignment": "left|right|rprompt|newline"
}

left: Primary prompt line, left-aligned
right: Same line as left, but right-aligned
rprompt: Right prompt (may overflow left)
newline: New prompt line

Multi-Line Prompt Example

{
  "blocks": [
    {
      "alignment": "left",
      "segments": [
        { "type": "shell", "..." },
        { "type": "path", "..." }
      ]
    },
    {
      "alignment": "right",
      "segments": [
        { "type": "time", "..." },
        { "type": "battery", "..." }
      ]
    },
    {
      "alignment": "newline",
      "segments": [
        { "type": "text", "template": "❯" }
      ]
    }
  ]
}

Vertical Offset for Alignment

{
  "alignment": "left",
  "vertical_offset": 0,  // 0 = same line as previous, >0 = down, <0 = up
  "segments": [...]
}

Creating Spacers and Dividers

{
 "background": "transparent",
 "properties": {
  "prefix": "",
  "suffix": ""
 },
 "template": " ", // Single space
 "type": "text"
}

Creating Custom Segments

Using the Command Segment for Custom Logic

{
 "background": "p:blue_primary",
 "cache": {
  "strategy": "session",
  "duration": "30s"
 },
 "foreground": "p:white",
 "properties": {
  "shell": "powershell",
  "command": "Get-Process -Name 'notable-app' -ErrorAction SilentlyContinue | Measure-Object | ForEach-Object { $_.Count }",
  "parse": true
 },
 "template": "{{ .Output }}",
 "type": "command"
}

Custom PowerShell Script Segment

Create a PowerShell script that returns information:

# File: CustomSegments.ps1

function Get-GitStats {
    $ahead = (git rev-list --count "@{u}..HEAD" 2>/dev/null) || 0
    $behind = (git rev-list --count "HEAD..@{u}" 2>/dev/null) || 0

    if ($ahead -eq 0 -and $behind -eq 0) {
        return ""
    }

    $stats = @()
    if ($ahead -gt 0) { $stats += "↑$ahead" }
    if ($behind -gt 0) { $stats += "↓$behind" }

    return $stats -join " "
}

Get-GitStats

Configure in theme:

{
 "properties": {
  "shell": "powershell",
  "command": "&{ . ./CustomSegments.ps1; Get-GitStats }"
 },
 "template": "{{ .Output }}",
 "type": "command"
}

Environment Variable Segment

{
 "background": "p:purple_session",
 "cache": {
  "strategy": "session"
 },
 "foreground": "p:white",
 "properties": {
  "var_name": "ENVIRONMENT"
 },
 "template": "[{{ .Env.ENVIRONMENT }}]",
 "type": "env"
}

Performance Tuning

Segment Caching Strategies

Caching prevents expensive segment evaluations on every prompt.

Cache Strategy Types

{
 "cache": {
  "strategy": "session|folder|windows",
  "duration": "5m",
  "skip_cache": false
 }
}

session: Cache for entire shell session (fastest)
folder: Cache per directory (good for git status)
windows: Cache per PowerShell window session

Duration Format

"2s"    // 2 seconds
"5m"    // 5 minutes
"1h"    // 1 hour

Caching Best Practices

{
  "type": "git",
  "cache": {
    "strategy": "folder",
    "duration": "5m"
  }
},
{
  "type": "time",
  "cache": {
    "strategy": "session",
    "duration": "1s"  // Update every second
  }
},
{
  "type": "command",
  "cache": {
    "strategy": "session",
    "duration": "30s"  // Heavy commands should cache longer
  }
}

Disabling Expensive Segments

If a segment is very slow, consider disabling or replacing it:

{
 "background": "transparent",
 "properties": {
  "command": "..." // Expensive logic disabled
 },
 "template": "", // Empty template = hidden
 "type": "command"
}

Conditional Segment Loading

Load segments only in certain conditions:

{
 "properties": {
  "shell": "powershell",
  "command": "$PSVersionTable.PSVersion.Major"
 },
 "template": "{{ if eq .Shell \"pwsh\" }}⚡{{ end }}",
 "type": "command"
}

Best Practices

1. Modular Configuration

Separate concerns into distinct segments:

{
 "blocks": [
  {
   "type": "prompt",
   "alignment": "left",
   "segments": [
    { "type": "shell" }, // ① System info
    { "type": "path" }, // ② Location
    { "type": "git" } // ③ VCS status
   ]
  },
  {
   "type": "prompt",
   "alignment": "right",
   "segments": [
    { "type": "time" }, // ④ Clock
    { "type": "battery" } // ⑤ Power
   ]
  }
 ]
}

2. Consistent Styling

Use palette colors consistently:

{
 "blocks": [
  {
   "segments": [
    {
     "background": "p:bg_primary",
     "foreground": "p:fg_primary"
    }
   ]
  }
 ],
 "palette": {
  "bg_primary": "#1e1e2e",
  "bg_secondary": "#313244",
  "fg_primary": "#cdd6f4"
 }
}

3. Performance First

Cache aggressively and consider disabling optional segments:

{
 "cache": {
  "strategy": "folder",
  "duration": "5m"
 },
 "properties": {
  "fetch_status": true, // Only when needed
  "fetch_upstream_icon": false // Optional detail
 }
}

4. Readability

Ensure adequate contrast and spacing:

{
 "background": "p:dark_color",
 "foreground": "p:light_color", // High contrast
 "template": "  {{ .Content }}  " // Breathing room
}

5. Testing Changes

Test your modifications before deploying:

# Test a modified theme
oh-my-posh init pwsh --config './my-modified-theme.json' | Invoke-Expression

# Reload if needed
$ExecutionContext.InvokeCommand.LocationChangedAction = $null
& $profile

Summary

Advanced customization allows you to:

✅ Create highly personal prompts ✅ Integrate custom scripts and commands ✅ Optimize for your specific workflow ✅ Reduce visual clutter or add detail ✅ Maintain consistent branding

Key Areas Covered:

Theme Structure: Understanding JSON schema
Segments: Customizing built-in segment types
Templates: Writing dynamic template expressions
Icons: Adding visual richness
Colors: Palette system and conditional colors
Layouts: Multi-line and complex block arrangements
Custom Logic: Command segments and scripts
Performance: Caching and optimization
Best Practices: Professional configuration techniques

For more advanced topics, refer to the Official Oh My Posh Documentation.