chore(master): release 1.9.0

.github/workflows/manual-homebrew-release.yml

@@ -3,40 +3,10 @@ name: Manual Homebrew Release
 on:
   workflow_dispatch:
 
-permissions:
-  contents: read
-
 jobs:
-  release-homebrew:
-    name: Trigger Homebrew Formula Update
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Get latest tag
-        id: latest
-        run: |
-          tag=$(gh release view --json tagName -q .tagName)
-          echo "Latest release tag: $tag"
-          echo "tag=$tag" >> "$GITHUB_OUTPUT"
-        env:
-          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Send dispatch to homebrew-tap
-        env:
-          GH_TOKEN: ${{ secrets.REPO_DISPATCH_PAT }}
-        run: |
-          tag="${{ steps.latest.outputs.tag }}"
-          repo="${{ github.event.repository.name }}"
-          data="{\"event_type\":\"trigger-from-release\",\"client_payload\":{\"tag\":\"$tag\",\"repo\":\"$repo\"}}"
-          echo "Dispatching tag $tag from $repo"
-          echo "Data: $data"
-          curl -X POST \
-            -H "Accept: application/vnd.github+json" \
-            -H "Authorization: Bearer $GH_TOKEN" \
-            https://api.github.com/repos/chenasraf/homebrew-tap/dispatches \
-            -d "$data"
-          echo "Dispatched tag $tag from $repo"
-          echo "Created job on https://github.com/chenasraf/homebrew-tap/actions"
+  homebrew:
+    uses: chenasraf/workflows/.github/workflows/manual-homebrew-release.yml@master
+    with:
+      homebrew-tap-repo: chenasraf/homebrew-tap
+    secrets:
+      REPO_DISPATCH_PAT: ${{ secrets.REPO_DISPATCH_PAT }}

.github/workflows/release.yml

@@ -11,114 +11,10 @@ permissions:
   pull-requests: write
 
 jobs:
-  test:
-    name: Test
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up Go
-        uses: actions/setup-go@v4
-        with:
-          go-version: '1.23'
-      - name: Test
-        run: go test -v ./...
-
-  generate:
-    name: Build for ${{ matrix.platform }}
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        include:
-          - platform: linux/amd64
-            label: linux-amd64
-          - platform: darwin/amd64
-            label: darwin-amd64
-          - platform: darwin/arm64
-            label: darwin-arm64
-          - platform: windows/amd64
-            label: windows-amd64
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Build for ${{ matrix.label }}
-        uses: chenasraf/go-cross-build@v1
-        with:
-          platforms: ${{ matrix.platform }}
-          package: ''
-          name: 'watchr'
-          compress: 'true'
-          dest: dist
-
-      - name: Upload build
-        uses: actions/upload-artifact@v4
-        with:
-          name: "dist-${{ matrix.label }}"
-          path: dist
-
-  release-please:
-    name: Release
-    if: github.ref == 'refs/heads/master'
-    runs-on: ubuntu-latest
-    outputs:
-      release_created: ${{ steps.release.outputs.release_created }}
-      tag_name: ${{ steps.release.outputs.tag_name }}
-    needs:
-      - test
-      - generate
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Download all builds
-        uses: actions/download-artifact@v4
-        with:
-          path: dist
-
-      - name: Verify Release Artifacts
-        run: |
-          ls -la dist
-          for i in "linux-amd64" "darwin-amd64" "windows-amd64" "darwin-arm64"; do
-            if [[ ! -f ./dist/dist-$i/watchr-$i.tar.gz ]]; then
-              echo "File not found: ./dist/dist-$i/watchr-$i.tar.gz"
-              exit 1
-            fi
-          done
-
-      - name: Run Release Please
-        uses: googleapis/release-please-action@v4
-        id: release
-        with:
-          release-type: simple
-
-      - name: Upload Release Artifacts
-        if: ${{ steps.release.outputs.release_created }}
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        run: |
-          for i in "linux-amd64" "darwin-amd64" "darwin-arm64" "windows-amd64"; do
-            gh release upload "${{ steps.release.outputs.tag_name }}" "./dist/dist-$i/watchr-$i.tar.gz"
-          done
-
-  release-homebrew:
-    name: Homebrew Release
-    needs: [release-please]
-    if: ${{ needs.release-please.outputs.release_created }}
-    runs-on: ubuntu-latest
-    steps:
-      - name: Send dispatch to homebrew-tap
-        env:
-          GH_TOKEN: ${{ secrets.REPO_DISPATCH_PAT }}
-        run: |
-          repo="${{ github.event.repository.name }}"
-          tag="${{ needs.release-please.outputs.tag_name }}"
-          data="{\"event_type\":\"trigger-from-release\",\"client_payload\":{\"tag\":\"$tag\",\"repo\":\"$repo\"}}"
-          echo "Dispatching tag $tag from $repo"
-          echo "Data: $data"
-          curl -X POST \
-            -H "Accept: application/vnd.github+json" \
-            -H "Authorization: Bearer $GH_TOKEN" \
-            https://api.github.com/repos/chenasraf/homebrew-tap/dispatches \
-            -d "$data"
-          echo "Dispatched tag $tag from $repo"
-          echo "Created job on https://github.com/chenasraf/homebrew-tap/actions"
+  release:
+    uses: chenasraf/workflows/.github/workflows/go-release.yml@master
+    with:
+      name: watchr
+      homebrew-tap-repo: chenasraf/homebrew-tap
+    secrets:
+      REPO_DISPATCH_PAT: ${{ secrets.REPO_DISPATCH_PAT }}

.golangci.yml

@@ -0,0 +1,12 @@
+version: "2"
+
+linters:
+  enable:
+    - staticcheck
+    - govet
+    - errcheck
+    - ineffassign
+    - unused
+    - gocritic
+    - intrange
+    - modernize

CHANGELOG.md

@@ -1,5 +1,81 @@
 # Changelog
 
+## [1.9.0](https://github.com/chenasraf/watchr/compare/v1.8.0...v1.9.0) (2026-03-16)
+
+
+### Features
+
+* add copy as plain ([85437c7](https://github.com/chenasraf/watchr/commit/85437c7ce0432a1bfce07e51bda90f4800d2059a))
+
+## [1.8.0](https://github.com/chenasraf/watchr/compare/v1.7.0...v1.8.0) (2026-03-14)
+
+
+### Features
+
+* command pallete ([140574e](https://github.com/chenasraf/watchr/commit/140574e512a03e5ddaa70af03c66d83a0d00d5fb))
+* J/K to scroll preview pane ([0c6fc52](https://github.com/chenasraf/watchr/commit/0c6fc521bca0d4781caa2a26ae16bc802a2164d9))
+* preview window json syntax highlighting ([1bd3722](https://github.com/chenasraf/watchr/commit/1bd37227c48593994298cf572edc2a79c8f88ee9))
+* regex filtering + cursor filter navigation ([3133051](https://github.com/chenasraf/watchr/commit/31330513f812c148370d6cdc4fb94dadc5884411))
+* resize preview pane with +/- ([5174073](https://github.com/chenasraf/watchr/commit/51740732362d7a74235ee3ffbc66abd3ca4f43d8))
+
+
+### Bug Fixes
+
+* accept all characters when filtering ([0f67db3](https://github.com/chenasraf/watchr/commit/0f67db342f6d7aa01caba1a89124305204cf7c4a))
+* continue existing filter when entering filter mode ([561c98a](https://github.com/chenasraf/watchr/commit/561c98ae02563482aec054ef4deb30ba3ff8c9f1))
+
+## [1.7.0](https://github.com/chenasraf/watchr/compare/v1.6.0...v1.7.0) (2026-01-26)
+
+
+### Features
+
+* add keybinding 'c' to stop running command ([9df4fb8](https://github.com/chenasraf/watchr/commit/9df4fb8285a0181d29cfc6034165ce7cb21ab14b))
+
+## [1.6.0](https://github.com/chenasraf/watchr/compare/v1.5.2...v1.6.0) (2026-01-24)
+
+
+### Features
+
+* add refresh countdown timer ([63b4530](https://github.com/chenasraf/watchr/commit/63b45309b76def1b5be9c11d5228d97bb7ab0a6d))
+* add refresh-from-start setting ([f520a8b](https://github.com/chenasraf/watchr/commit/f520a8b4ed665c3187bab88707df9e5efdc779bc))
+* reset refresh timer after manual refresh ([10a9208](https://github.com/chenasraf/watchr/commit/10a92082b6c11fcfba2bd835ed2336d1f33d1c04))
+* stream new output in-place without resetting existing output ([8aaf514](https://github.com/chenasraf/watchr/commit/8aaf5148ab17b33a72ff3f946c57029c33bdb4d0))
+
+
+### Bug Fixes
+
+* streaming cursor position ([347ac34](https://github.com/chenasraf/watchr/commit/347ac340942c3ee8d2731432f808ac2b9dd39060))
+
+## [1.5.2](https://github.com/chenasraf/watchr/compare/v1.5.1...v1.5.2) (2026-01-24)
+
+
+### Bug Fixes
+
+* tab characters breaking the layout ([c09d3e4](https://github.com/chenasraf/watchr/commit/c09d3e41ddd69c44ea0546cb0608abe8b0c50334))
+
+## [1.5.1](https://github.com/chenasraf/watchr/compare/v1.5.0...v1.5.1) (2025-12-31)
+
+
+### Bug Fixes
+
+* esc button behavior ([5703a61](https://github.com/chenasraf/watchr/commit/5703a61ddb3ee25e58470c537d53bf4a463bc632))
+
+## [1.5.0](https://github.com/chenasraf/watchr/compare/v1.4.0...v1.5.0) (2025-12-14)
+
+
+### Features
+
+* add more refresh duration options & formats ([f15b9e2](https://github.com/chenasraf/watchr/commit/f15b9e255988b5b754c377e3ae29f9eb4c8a1925))
+
+## [1.4.0](https://github.com/chenasraf/watchr/compare/v1.3.0...v1.4.0) (2025-12-08)
+
+
+### Features
+
+* add -i/--interactive mode ([9ecf9f7](https://github.com/chenasraf/watchr/commit/9ecf9f74b7e8271dc8f8d2e6e2fc562e87be9953))
+* add spinning loader animation ([ed2f24c](https://github.com/chenasraf/watchr/commit/ed2f24c0e820ebaa37f46cc2407648c3e8b1cbbd))
+* properly support streaming commands ([66c6599](https://github.com/chenasraf/watchr/commit/66c65995068181d4b4ae74087eb0c15e1ab0edb4))
+
 ## [1.3.0](https://github.com/chenasraf/watchr/compare/v1.2.0...v1.3.0) (2025-12-04)
 
 

Makefile

@@ -1,6 +1,11 @@
 BIN := $(notdir $(CURDIR))
 
-all: run
+all:
+	@if [ ! -f ".git/hooks/pre-commit" ]; then \
+		$(MAKE) precommit-install; \
+	fi
+	$(MAKE) build
+	$(MAKE) run
 
 .PHONY: build
 build:

README.md

@@ -7,13 +7,16 @@ provides vim-style navigation, filtering, and a preview pane—all without leavi
 ![Downloads](https://img.shields.io/github/downloads/chenasraf/watchr/total)
 ![License](https://img.shields.io/github/license/chenasraf/watchr)
 
+![Promo](https://github.com/user-attachments/assets/ec5ab94b-ef91-40d8-a604-9047212a8faf)
+
 ---
 
 ## 🚀 Features
 
 - **Interactive output viewer**: Browse command output with vim-style keybindings
-- **Live filtering**: Press `/` to filter output lines in real-time
-- **Preview pane**: Toggle a preview panel (bottom, top, left, or right)
+- **Live filtering**: Press `/` to filter output lines in real-time, with regex support (`//`)
+- **Preview pane**: Toggle a resizable preview panel (bottom, top, left, or right) with JSON syntax
+  highlighting
 - **Auto-refresh**: Optionally re-run commands at specified intervals
 - **Line numbers**: Optional line numbering with configurable width
 - **Config files**: YAML, TOML, or JSON config files for persistent settings
@@ -76,6 +79,18 @@ watchr "ps aux"
 # Refresh every 2 seconds
 watchr -r 2 "docker ps"
 
+# Refresh every 500 milliseconds
+watchr -r 500ms "date"
+
+# Refresh every 1.5 seconds
+watchr -r 1.5s "kubectl get pods"
+
+# Refresh every 5 minutes
+watchr -r 5m "df -h"
+
+# Refresh every hour
+watchr -r 1h "curl -s https://api.example.com/status"
+
 # Watch file changes
 watchr -r 5 "find . -name '*.go' -mmin -1"
 ```
@@ -86,24 +101,27 @@ watchr -r 5 "find . -name '*.go' -mmin -1"
 Usage: watchr [options] <command to run>
 
 Options:
-  -h, --help                       Show help
-  -v, --version                    Show version
-  -c, --config string              Load config from specified path
-  -C, --show-config                Show loaded configuration and exit
-  -r, --refresh int                Auto-refresh interval in seconds (0 = disabled)
-  -p, --prompt string              Prompt string (default "watchr> ")
-  -s, --shell string               Shell to use for executing commands (default "sh")
-  -n, --no-line-numbers            Disable line numbers
-  -w, --line-width int             Line number width (default 6)
-  -P, --preview-size string        Preview size: number for lines/cols, or number% for percentage (default "40%")
-  -o, --preview-position string    Preview position: bottom, top, left, right (default "bottom")
+  -c, --config string             Load config from specified path
+  -h, --help                      Show help
+  -i, --interactive               Run shell in interactive mode (sources ~/.bashrc, ~/.zshrc, etc.)
+  -w, --line-width int            Line number width (default 6)
+  -n, --no-line-numbers           Disable line numbers
+  -o, --preview-position string   Preview position: bottom, top, left, right (default "bottom")
+  -P, --preview-size string       Preview size: number for lines/cols, or number% for percentage (e.g., 10 or 40%) (default "40%")
+  -p, --prompt string             Prompt string (default "watchr> ")
+  -r, --refresh string            Auto-refresh interval (e.g., 1, 1.5, 500ms, 2s, 5m, 1h; default unit: seconds, 0 = disabled) (default "0")
+      --refresh-from-start        Start refresh timer when command starts (default: when command ends)
+  -s, --shell string              Shell to use for executing commands (default "sh")
+  -C, --show-config               Show loaded configuration and exit
+  -v, --version                   Show version
 ```
 
 ---
 
 ## 📁 Configuration File
 
-`watchr` supports configuration files in YAML, TOML, or JSON format. Settings in config files serve as defaults that can be overridden by command-line flags.
+`watchr` supports configuration files in YAML, TOML, or JSON format. Settings in config files serve
+as defaults that can be overridden by command-line flags.
 
 ### Config File Locations
 
@@ -116,17 +134,20 @@ Config files are searched in the following order (later files override earlier o
 ### Example Configurations
 
 **YAML** (`watchr.yaml`):
+
 ```yaml
 shell: bash
-preview-size: "50%"
+preview-size: '50%'
 preview-position: right
 line-numbers: true
 line-width: 4
-prompt: "> "
-refresh: 0
+prompt: '> '
+refresh: 0 # disabled; or use: 2, 1.5, "500ms", "2s", "5m", "1h"
+interactive: false
 ```
 
 **TOML** (`watchr.toml`):
+
 ```toml
 shell = "bash"
 preview-size = "50%"
@@ -134,10 +155,12 @@ preview-position = "right"
 line-numbers = true
 line-width = 4
 prompt = "> "
-refresh = 0
+refresh = 0 # disabled; or use: 2, 1.5, "500ms", "2s", "5m", "1h"
+interactive = false
 ```
 
 **JSON** (`watchr.json`):
+
 ```json
 {
   "shell": "bash",
@@ -146,10 +169,16 @@ refresh = 0
   "line-numbers": true,
   "line-width": 4,
   "prompt": "> ",
-  "refresh": 0
+  "refresh": 0,
+  "interactive": false
 }
 ```
 
+The `refresh` option accepts:
+
+- Numbers: `2` or `1.5` (interpreted as seconds)
+- Explicit units: `"500ms"`, `"2s"`, `"5m"`, `"1h"`
+
 ### Priority Order
 
 Configuration values are applied in this order (later sources override earlier ones):
@@ -163,21 +192,41 @@ Configuration values are applied in this order (later sources override earlier o
 
 ## ⌨️ Keybindings
 
-| Key                | Action                          |
-| ------------------ | ------------------------------- |
-| `r`, `Ctrl-r`      | Reload (re-run command)         |
-| `q`, `Esc`         | Quit                            |
-| `j`, `k`           | Move down/up                    |
-| `g`                | Go to first line                |
-| `G`                | Go to last line                 |
-| `Ctrl-d`, `Ctrl-u` | Half page down/up               |
-| `PgDn`, `Ctrl-f`   | Full page down                  |
-| `PgUp`, `Ctrl-b`   | Full page up                    |
-| `p`                | Toggle preview pane             |
-| `/`                | Enter filter mode               |
-| `Esc`              | Exit filter mode / clear filter |
-| `y`                | Yank (copy) selected line       |
-| `?`                | Show help overlay               |
+| Key                | Action                           |
+| ------------------ | -------------------------------- |
+| `r`, `Ctrl-r`      | Reload (re-run command)          |
+| `c`                | Stop running command             |
+| `q`, `Esc`         | Quit                             |
+| `j`, `k`           | Move down/up                     |
+| `g`                | Go to first line                 |
+| `G`                | Go to last line                  |
+| `Ctrl-d`, `Ctrl-u` | Half page down/up                |
+| `PgDn`, `Ctrl-f`   | Full page down                   |
+| `PgUp`, `Ctrl-b`   | Full page up                     |
+| `p`                | Toggle preview pane              |
+| `+` / `-`          | Increase / decrease preview size |
+| `J` / `K`          | Scroll preview down / up         |
+| `/`                | Enter filter mode                |
+| `//`               | Toggle regex filter mode         |
+| `Esc`              | Exit filter mode / clear filter  |
+| `y`                | Yank (copy) selected line        |
+| `Y`                | Yank selected line (plain text)  |
+| `:`                | Open command palette             |
+| `?`                | Show help overlay                |
+
+### Filter mode
+
+When in filter mode (`/`), the following keys are available:
+
+| Key                      | Action                                   |
+| ------------------------ | ---------------------------------------- |
+| `Enter`                  | Confirm filter                           |
+| `Esc`                    | Cancel and clear filter                  |
+| `Left` / `Right`         | Move cursor within filter                |
+| `Alt-Left` / `Alt-Right` | Move cursor by word                      |
+| `Backspace`              | Delete character before cursor           |
+| `Alt-Backspace`          | Delete word before cursor                |
+| `/`                      | Toggle regex mode (when filter is empty) |
 
 ---
 
@@ -188,7 +237,7 @@ very helpful to sustaining its life. If you are feeling incredibly generous and
 just a small amount to help sustain this project, I would be very very thankful!
 
 <a href='https://ko-fi.com/casraf' target='_blank'>
-<img height='36' style='border:0px;height:36px;' src='https://cdn.ko-fi.com/cdn/kofi1.png?v=3' alt='Buy Me a Coffee at ko-fi.com' />
+  <img height='36' style='border:0px;height:36px;' src='https://cdn.ko-fi.com/cdn/kofi1.png?v=3' alt='Buy Me a Coffee at ko-fi.com' />
 </a>
 
 I welcome any issues or pull requests on GitHub. If you find a bug, or would like a new feature,

go.mod

@@ -12,11 +12,13 @@ require (
 )
 
 require (
+	github.com/alecthomas/chroma/v2 v2.23.1 // indirect
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
 	github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc // indirect
 	github.com/charmbracelet/x/ansi v0.10.1 // indirect
 	github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd // indirect
 	github.com/charmbracelet/x/term v0.2.1 // indirect
+	github.com/dlclark/regexp2 v1.11.5 // indirect
 	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
 	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect

go.sum

@@ -1,3 +1,5 @@
+github.com/alecthomas/chroma/v2 v2.23.1 h1:nv2AVZdTyClGbVQkIzlDm/rnhk1E9bU9nXwmZ/Vk/iY=
+github.com/alecthomas/chroma/v2 v2.23.1/go.mod h1:NqVhfBR0lte5Ouh3DcthuUCTUpDC9cxBOfyMbMQPs3o=
 github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
 github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
 github.com/charmbracelet/bubbletea v1.3.10 h1:otUDHWMMzQSB0Pkc87rm691KZ3SWa4KUlvF9nRvCICw=
@@ -14,6 +16,8 @@ github.com/charmbracelet/x/term v0.2.1 h1:AQeHeLZ1OqSXhrAWpYUtZyX1T3zVxfpZuEQMIQ
 github.com/charmbracelet/x/term v0.2.1/go.mod h1:oQ4enTYFV7QN4m0i9mzHrViD7TQKvNEEkHUMCmsxdUg=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/dlclark/regexp2 v1.11.5 h1:Q/sSnsKerHeCkc/jSTNq1oCm7KiVgUMZRDUoRu0JQZQ=
+github.com/dlclark/regexp2 v1.11.5/go.mod h1:DHkYz0B9wPfa6wondMfaivmHpzrQ3v9q8cnmRbL6yW8=
 github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f h1:Y/CXytFA4m6baUTXGLOoWe4PQhGxaX0KpnayAqC48p4=
 github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f/go.mod h1:vw97MGsxSvLiUE2X8qFplwetxpGLQrlU1Q9AUEIzCaM=
 github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=

internal/config/config.go

@@ -4,7 +4,10 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
 	"runtime"
+	"strconv"
+	"time"
 
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
@@ -12,13 +15,15 @@ import (
 
 // Config keys
 const (
-	KeyShell           = "shell"
-	KeyPreviewSize     = "preview-size"
-	KeyPreviewPosition = "preview-position"
-	KeyLineNumbers     = "line-numbers"
-	KeyLineWidth       = "line-width"
-	KeyPrompt          = "prompt"
-	KeyRefresh         = "refresh"
+	KeyShell            = "shell"
+	KeyPreviewSize      = "preview-size"
+	KeyPreviewPosition  = "preview-position"
+	KeyLineNumbers      = "line-numbers"
+	KeyLineWidth        = "line-width"
+	KeyPrompt           = "prompt"
+	KeyRefresh          = "refresh"
+	KeyRefreshFromStart = "refresh-from-start"
+	KeyInteractive      = "interactive"
 )
 
 // setDefaults sets the default configuration values.
@@ -29,7 +34,9 @@ func setDefaults() {
 	viper.SetDefault(KeyLineNumbers, true)
 	viper.SetDefault(KeyLineWidth, 6)
 	viper.SetDefault(KeyPrompt, "watchr> ")
-	viper.SetDefault(KeyRefresh, 0)
+	viper.SetDefault(KeyRefresh, "0")
+	viper.SetDefault(KeyRefreshFromStart, false)
+	viper.SetDefault(KeyInteractive, false)
 }
 
 // Init initializes Viper with config file paths and defaults.
@@ -74,6 +81,8 @@ func BindFlags(flags *pflag.FlagSet) {
 	_ = viper.BindPFlag(KeyLineWidth, flags.Lookup("line-width"))
 	_ = viper.BindPFlag(KeyPrompt, flags.Lookup("prompt"))
 	_ = viper.BindPFlag(KeyRefresh, flags.Lookup("refresh"))
+	_ = viper.BindPFlag(KeyRefreshFromStart, flags.Lookup("refresh-from-start"))
+	_ = viper.BindPFlag(KeyInteractive, flags.Lookup("interactive"))
 
 	// line-numbers is inverted (no-line-numbers flag)
 	_ = viper.BindPFlag("no-line-numbers", flags.Lookup("no-line-numbers"))
@@ -126,7 +135,9 @@ func PrintConfig() {
 	fmt.Printf("  %-20s %v\n", KeyLineNumbers+":", GetBool(KeyLineNumbers))
 	fmt.Printf("  %-20s %d\n", KeyLineWidth+":", GetInt(KeyLineWidth))
 	fmt.Printf("  %-20s %q\n", KeyPrompt+":", GetString(KeyPrompt))
-	fmt.Printf("  %-20s %d\n", KeyRefresh+":", GetInt(KeyRefresh))
+	fmt.Printf("  %-20s %s\n", KeyRefresh+":", GetString(KeyRefresh))
+	fmt.Printf("  %-20s %v\n", KeyRefreshFromStart+":", GetBool(KeyRefreshFromStart))
+	fmt.Printf("  %-20s %v\n", KeyInteractive+":", GetBool(KeyInteractive))
 }
 
 // getConfigDir returns the appropriate config directory for the OS.
@@ -145,3 +156,57 @@ func getConfigDir() string {
 		return ""
 	}
 }
+
+// durationRegex matches duration strings like "1", "1.5", "500ms", "1s", "1.5s", "5m", "1h"
+var durationRegex = regexp.MustCompile(`^(\d+(?:\.\d+)?)(ms|s|m|h)?$`)
+
+// ParseDuration parses a duration string into a time.Duration.
+// Supported formats:
+//   - "1", "1.5" - interpreted as seconds (default unit)
+//   - "1s", "1.5s" - explicit seconds
+//   - "500ms", "1500ms" - explicit milliseconds
+//   - "5m", "1.5m" - explicit minutes
+//   - "1h", "0.5h" - explicit hours
+//
+// Returns 0 if the input is empty or "0".
+func ParseDuration(s string) (time.Duration, error) {
+	if s == "" || s == "0" {
+		return 0, nil
+	}
+
+	matches := durationRegex.FindStringSubmatch(s)
+	if matches == nil {
+		return 0, fmt.Errorf("invalid duration format: %q (expected number, Xms, Xs, Xm, or Xh)", s)
+	}
+
+	value, err := strconv.ParseFloat(matches[1], 64)
+	if err != nil {
+		return 0, fmt.Errorf("invalid duration value: %q", matches[1])
+	}
+
+	unit := matches[2]
+	switch unit {
+	case "ms":
+		return time.Duration(value * float64(time.Millisecond)), nil
+	case "s", "":
+		// Default to seconds
+		return time.Duration(value * float64(time.Second)), nil
+	case "m":
+		return time.Duration(value * float64(time.Minute)), nil
+	case "h":
+		return time.Duration(value * float64(time.Hour)), nil
+	default:
+		return 0, fmt.Errorf("invalid duration unit: %q", unit)
+	}
+}
+
+// GetDuration returns a duration config value by parsing the string value.
+// Returns 0 if parsing fails or value is empty.
+func GetDuration(key string) time.Duration {
+	s := viper.GetString(key)
+	d, err := ParseDuration(s)
+	if err != nil {
+		return 0
+	}
+	return d
+}

internal/config/config_test.go

@@ -4,6 +4,7 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+	"time"
 
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
@@ -70,8 +71,8 @@ func TestInit(t *testing.T) {
 		t.Errorf("expected default prompt 'watchr> ', got %q", got)
 	}
 
-	if got := viper.GetInt(KeyRefresh); got != 0 {
-		t.Errorf("expected default refresh 0, got %d", got)
+	if got := viper.GetString(KeyRefresh); got != "0" {
+		t.Errorf("expected default refresh '0', got %q", got)
 	}
 }
 
@@ -131,8 +132,10 @@ func TestBindFlags(t *testing.T) {
 	flags.String("preview-position", "bottom", "")
 	flags.Int("line-width", 6, "")
 	flags.String("prompt", "watchr> ", "")
-	flags.Int("refresh", 0, "")
+	flags.String("refresh", "0", "")
+	flags.Bool("refresh-from-start", false, "")
 	flags.Bool("no-line-numbers", false, "")
+	flags.Bool("interactive", false, "")
 
 	// Parse with custom values
 	err := flags.Parse([]string{"--shell=bash", "--preview-size=50%", "--line-width=8"})
@@ -204,8 +207,8 @@ refresh: 5
 		t.Errorf("expected prompt 'test> ' from config file, got %q", got)
 	}
 
-	if got := GetInt(KeyRefresh); got != 5 {
-		t.Errorf("expected refresh 5 from config file, got %d", got)
+	if got := GetDuration(KeyRefresh); got != 5*time.Second {
+		t.Errorf("expected refresh 5s from config file, got %v", got)
 	}
 
 	// ConfigFileUsed should return the path
@@ -237,8 +240,10 @@ preview-size: "60%"
 	flags.String("preview-position", "bottom", "")
 	flags.Int("line-width", 6, "")
 	flags.String("prompt", "watchr> ", "")
-	flags.Int("refresh", 0, "")
+	flags.String("refresh", "0", "")
+	flags.Bool("refresh-from-start", false, "")
 	flags.Bool("no-line-numbers", false, "")
+	flags.Bool("interactive", false, "")
 
 	// Override shell via flag
 	err := flags.Parse([]string{"--shell=bash"})
@@ -322,8 +327,8 @@ refresh: 10
 		t.Errorf("expected prompt 'custom> ', got %q", got)
 	}
 
-	if got := GetInt(KeyRefresh); got != 10 {
-		t.Errorf("expected refresh 10, got %d", got)
+	if got := GetDuration(KeyRefresh); got != 10*time.Second {
+		t.Errorf("expected refresh 10s, got %v", got)
 	}
 
 	// ConfigFileUsed should return the specified path
@@ -434,3 +439,279 @@ func TestInitWithFileDefaults(t *testing.T) {
 		t.Errorf("expected default line-width 6, got %d", got)
 	}
 }
+
+func TestParseDuration(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected time.Duration
+		wantErr  bool
+	}{
+		// Empty and zero values
+		{"", 0, false},
+		{"0", 0, false},
+
+		// Plain numbers (default to seconds)
+		{"1", 1 * time.Second, false},
+		{"5", 5 * time.Second, false},
+		{"60", 60 * time.Second, false},
+
+		// Decimal seconds
+		{"0.5", 500 * time.Millisecond, false},
+		{"1.5", 1500 * time.Millisecond, false},
+		{"2.25", 2250 * time.Millisecond, false},
+		{"0.1", 100 * time.Millisecond, false},
+		{"0.001", 1 * time.Millisecond, false},
+
+		// Explicit seconds suffix
+		{"1s", 1 * time.Second, false},
+		{"5s", 5 * time.Second, false},
+		{"0.5s", 500 * time.Millisecond, false},
+		{"1.5s", 1500 * time.Millisecond, false},
+
+		// Milliseconds suffix
+		{"100ms", 100 * time.Millisecond, false},
+		{"500ms", 500 * time.Millisecond, false},
+		{"1000ms", 1000 * time.Millisecond, false},
+		{"1500ms", 1500 * time.Millisecond, false},
+		{"50.5ms", 50500 * time.Microsecond, false},
+
+		// Minutes suffix
+		{"1m", 1 * time.Minute, false},
+		{"5m", 5 * time.Minute, false},
+		{"0.5m", 30 * time.Second, false},
+		{"1.5m", 90 * time.Second, false},
+
+		// Hours suffix
+		{"1h", 1 * time.Hour, false},
+		{"2h", 2 * time.Hour, false},
+		{"0.5h", 30 * time.Minute, false},
+		{"1.5h", 90 * time.Minute, false},
+
+		// Invalid formats
+		{"abc", 0, true},
+		{"1d", 0, true},  // days not supported
+		{"1w", 0, true},  // weeks not supported
+		{"-1", 0, true},  // negative not supported
+		{"-1s", 0, true}, // negative not supported
+		{"1.2.3", 0, true},
+		{"s", 0, true},
+		{"ms", 0, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			got, err := ParseDuration(tt.input)
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("ParseDuration(%q) expected error, got nil", tt.input)
+				}
+				return
+			}
+			if err != nil {
+				t.Errorf("ParseDuration(%q) unexpected error: %v", tt.input, err)
+				return
+			}
+			if got != tt.expected {
+				t.Errorf("ParseDuration(%q) = %v, want %v", tt.input, got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestGetDuration(t *testing.T) {
+	_, cleanup := isolateConfig(t)
+	defer cleanup()
+
+	Init()
+
+	// Test default value
+	if got := GetDuration(KeyRefresh); got != 0 {
+		t.Errorf("expected default refresh 0, got %v", got)
+	}
+
+	// Test with seconds value
+	viper.Set(KeyRefresh, "5")
+	if got := GetDuration(KeyRefresh); got != 5*time.Second {
+		t.Errorf("expected refresh 5s, got %v", got)
+	}
+
+	// Test with decimal value
+	viper.Set(KeyRefresh, "0.5")
+	if got := GetDuration(KeyRefresh); got != 500*time.Millisecond {
+		t.Errorf("expected refresh 500ms, got %v", got)
+	}
+
+	// Test with explicit seconds suffix
+	viper.Set(KeyRefresh, "2s")
+	if got := GetDuration(KeyRefresh); got != 2*time.Second {
+		t.Errorf("expected refresh 2s, got %v", got)
+	}
+
+	// Test with milliseconds
+	viper.Set(KeyRefresh, "250ms")
+	if got := GetDuration(KeyRefresh); got != 250*time.Millisecond {
+		t.Errorf("expected refresh 250ms, got %v", got)
+	}
+
+	// Test with invalid value (should return 0)
+	viper.Set(KeyRefresh, "invalid")
+	if got := GetDuration(KeyRefresh); got != 0 {
+		t.Errorf("expected refresh 0 for invalid value, got %v", got)
+	}
+}
+
+func TestRefreshFromStartDefault(t *testing.T) {
+	_, cleanup := isolateConfig(t)
+	defer cleanup()
+
+	Init()
+
+	// Default should be false
+	if got := GetBool(KeyRefreshFromStart); got != false {
+		t.Errorf("expected default refresh-from-start false, got %v", got)
+	}
+}
+
+func TestRefreshFromStartFromConfigFile(t *testing.T) {
+	tmpDir, cleanup := isolateConfig(t)
+	defer cleanup()
+
+	// Create config file with refresh-from-start: true
+	configPath := filepath.Join(tmpDir, "watchr.yaml")
+	configContent := `refresh-from-start: true
+`
+	if err := os.WriteFile(configPath, []byte(configContent), 0644); err != nil {
+		t.Fatalf("failed to write config file: %v", err)
+	}
+
+	Init()
+
+	if got := GetBool(KeyRefreshFromStart); got != true {
+		t.Errorf("expected refresh-from-start true from config file, got %v", got)
+	}
+}
+
+func TestRefreshFromStartFromFlag(t *testing.T) {
+	_, cleanup := isolateConfig(t)
+	defer cleanup()
+
+	Init()
+
+	// Create flags and parse
+	flags := pflag.NewFlagSet("test", pflag.ContinueOnError)
+	flags.String("shell", "sh", "")
+	flags.String("preview-size", "40%", "")
+	flags.String("preview-position", "bottom", "")
+	flags.Int("line-width", 6, "")
+	flags.String("prompt", "watchr> ", "")
+	flags.String("refresh", "0", "")
+	flags.Bool("refresh-from-start", false, "")
+	flags.Bool("no-line-numbers", false, "")
+	flags.Bool("interactive", false, "")
+
+	// Parse with refresh-from-start=true
+	err := flags.Parse([]string{"--refresh-from-start=true"})
+	if err != nil {
+		t.Fatalf("failed to parse flags: %v", err)
+	}
+
+	BindFlags(flags)
+
+	if got := GetBool(KeyRefreshFromStart); got != true {
+		t.Errorf("expected refresh-from-start true from flag, got %v", got)
+	}
+}
+
+func TestRefreshFromStartFlagOverridesConfig(t *testing.T) {
+	tmpDir, cleanup := isolateConfig(t)
+	defer cleanup()
+
+	// Create config file with refresh-from-start: true
+	configPath := filepath.Join(tmpDir, "watchr.yaml")
+	configContent := `refresh-from-start: true
+`
+	if err := os.WriteFile(configPath, []byte(configContent), 0644); err != nil {
+		t.Fatalf("failed to write config file: %v", err)
+	}
+
+	Init()
+
+	// Create flags and parse with refresh-from-start=false
+	flags := pflag.NewFlagSet("test", pflag.ContinueOnError)
+	flags.String("shell", "sh", "")
+	flags.String("preview-size", "40%", "")
+	flags.String("preview-position", "bottom", "")
+	flags.Int("line-width", 6, "")
+	flags.String("prompt", "watchr> ", "")
+	flags.String("refresh", "0", "")
+	flags.Bool("refresh-from-start", false, "")
+	flags.Bool("no-line-numbers", false, "")
+	flags.Bool("interactive", false, "")
+
+	err := flags.Parse([]string{"--refresh-from-start=false"})
+	if err != nil {
+		t.Fatalf("failed to parse flags: %v", err)
+	}
+
+	BindFlags(flags)
+
+	// Flag should override config
+	if got := GetBool(KeyRefreshFromStart); got != false {
+		t.Errorf("expected refresh-from-start false (flag override), got %v", got)
+	}
+}
+
+func TestRefreshDurationFromConfigFile(t *testing.T) {
+	tmpDir, cleanup := isolateConfig(t)
+	defer cleanup()
+
+	tests := []struct {
+		name     string
+		yaml     string
+		expected time.Duration
+	}{
+		{
+			name:     "integer seconds",
+			yaml:     "refresh: 5\n",
+			expected: 5 * time.Second,
+		},
+		{
+			name:     "decimal seconds",
+			yaml:     "refresh: 0.5\n",
+			expected: 500 * time.Millisecond,
+		},
+		{
+			name:     "string with s suffix",
+			yaml:     "refresh: \"2s\"\n",
+			expected: 2 * time.Second,
+		},
+		{
+			name:     "string with ms suffix",
+			yaml:     "refresh: \"500ms\"\n",
+			expected: 500 * time.Millisecond,
+		},
+		{
+			name:     "string decimal with s suffix",
+			yaml:     "refresh: \"1.5s\"\n",
+			expected: 1500 * time.Millisecond,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			resetViper()
+
+			configPath := filepath.Join(tmpDir, "watchr.yaml")
+			if err := os.WriteFile(configPath, []byte(tt.yaml), 0644); err != nil {
+				t.Fatalf("failed to write config file: %v", err)
+			}
+
+			Init()
+
+			got := GetDuration(KeyRefresh)
+			if got != tt.expected {
+				t.Errorf("GetDuration(KeyRefresh) = %v, want %v", got, tt.expected)
+			}
+		})
+	}
+}

internal/runner/runner.go

@@ -5,11 +5,22 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"os"
 	"os/exec"
+	"path/filepath"
 	"strings"
 	"sync"
 )
 
+// sanitizeLine removes control sequences that can corrupt terminal rendering
+func sanitizeLine(s string) string {
+	// Remove carriage returns
+	s = strings.ReplaceAll(s, "\r", "")
+	// Convert tabs to spaces (tabs cause width calculation issues)
+	s = strings.ReplaceAll(s, "\t", "        ")
+	return s
+}
+
 // Line represents a single line of output with its line number
 type Line struct {
 	Number  int
@@ -26,15 +37,82 @@ func (l Line) FormatLine(width int, showLineNum bool) string {
 
 // Runner executes commands and captures output
 type Runner struct {
-	Shell   string
-	Command string
+	Shell       string
+	Command     string
+	Interactive bool
 }
 
 // NewRunner creates a new Runner
 func NewRunner(shell, command string) *Runner {
 	return &Runner{
-		Shell:   shell,
-		Command: command,
+		Shell:       shell,
+		Command:     command,
+		Interactive: false,
+	}
+}
+
+// NewInteractiveRunner creates a new Runner that sources shell rc files
+func NewInteractiveRunner(shell, command string) *Runner {
+	return &Runner{
+		Shell:       shell,
+		Command:     command,
+		Interactive: true,
+	}
+}
+
+// buildCommand returns the shell arguments for executing the command.
+// If Interactive is true, it wraps the command to source the appropriate rc file.
+func (r *Runner) buildCommand() []string {
+	if !r.Interactive {
+		return []string{"-c", r.Command}
+	}
+
+	// For interactive mode, source the appropriate rc file before running the command
+	rcFile := r.getRCFile()
+	if rcFile != "" {
+		// Source the rc file if it exists, then run the command
+		wrappedCmd := fmt.Sprintf("[ -f %s ] && . %s; %s", rcFile, rcFile, r.Command)
+		return []string{"-c", wrappedCmd}
+	}
+
+	return []string{"-c", r.Command}
+}
+
+// getRCFile returns the path to the shell's rc file based on the shell being used.
+func (r *Runner) getRCFile() string {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return ""
+	}
+
+	shellBase := filepath.Base(r.Shell)
+	switch shellBase {
+	case "bash":
+		// Prefer .bashrc for interactive settings, fall back to .bash_profile
+		bashrc := filepath.Join(home, ".bashrc")
+		if _, err := os.Stat(bashrc); err == nil {
+			return bashrc
+		}
+		return filepath.Join(home, ".bash_profile")
+	case "zsh":
+		return filepath.Join(home, ".zshrc")
+	case "fish":
+		configDir := os.Getenv("XDG_CONFIG_HOME")
+		if configDir == "" {
+			configDir = filepath.Join(home, ".config")
+		}
+		return filepath.Join(configDir, "fish", "config.fish")
+	case "ksh":
+		return filepath.Join(home, ".kshrc")
+	case "sh":
+		// POSIX sh uses ENV variable or .profile
+		if env := os.Getenv("ENV"); env != "" {
+			return env
+		}
+		return filepath.Join(home, ".profile")
+	default:
+		// Try common patterns for unknown shells
+		return filepath.Join(home, "."+shellBase+"rc")
 	}
 }
 
@@ -46,7 +124,9 @@ type Result struct {
 
 // Run executes the command and returns output lines with exit code
 func (r *Runner) Run(ctx context.Context) (Result, error) {
-	cmd := exec.CommandContext(ctx, r.Shell, "-c", r.Command)
+	args := r.buildCommand()
+	cmd := exec.CommandContext(ctx, r.Shell, args...)
+	cmd.Env = append(os.Environ(), "WATCHR=1")
 
 	stdout, err := cmd.StdoutPipe()
 	if err != nil {
@@ -70,7 +150,7 @@ func (r *Runner) Run(ctx context.Context) (Result, error) {
 	for scanner.Scan() {
 		lines = append(lines, Line{
 			Number:  lineNum,
-			Content: scanner.Text(),
+			Content: sanitizeLine(scanner.Text()),
 		})
 		lineNum++
 	}
@@ -80,7 +160,7 @@ func (r *Runner) Run(ctx context.Context) (Result, error) {
 	for stderrScanner.Scan() {
 		lines = append(lines, Line{
 			Number:  lineNum,
-			Content: stderrScanner.Text(),
+			Content: sanitizeLine(stderrScanner.Text()),
 		})
 		lineNum++
 	}
@@ -96,59 +176,168 @@ func (r *Runner) Run(ctx context.Context) (Result, error) {
 	return Result{Lines: lines, ExitCode: exitCode}, nil
 }
 
-// RunStreaming executes the command and streams output lines to the callback
-// The callback is called for each line as it arrives
-func (r *Runner) RunStreaming(ctx context.Context, lines *[]Line, mu *sync.RWMutex) error {
-	cmd := exec.CommandContext(ctx, r.Shell, "-c", r.Command)
+// StreamingResult holds the state of a streaming command
+type StreamingResult struct {
+	Lines            *[]Line
+	ExitCode         int
+	Done             bool
+	Error            error
+	PrevLineCount    int // Number of lines from previous run (for trimming)
+	CurrentLineCount int // Number of lines written by current run
+	mu               sync.RWMutex
+}
 
-	stdout, err := cmd.StdoutPipe()
-	if err != nil {
-		return fmt.Errorf("failed to create stdout pipe: %w", err)
+// GetLines returns a copy of the current lines (thread-safe)
+func (s *StreamingResult) GetLines() []Line {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	if s.Lines == nil {
+		return nil
+	}
+	result := make([]Line, len(*s.Lines))
+	copy(result, *s.Lines)
+	return result
+}
+
+// LineCount returns the current number of lines (thread-safe)
+func (s *StreamingResult) LineCount() int {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	if s.Lines == nil {
+		return 0
+	}
+	return len(*s.Lines)
+}
+
+// IsDone returns whether the command has finished (thread-safe)
+func (s *StreamingResult) IsDone() bool {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return s.Done
+}
+
+// GetCurrentLineCount returns the number of lines written by the current run (thread-safe)
+func (s *StreamingResult) GetCurrentLineCount() int {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return s.CurrentLineCount
+}
+
+// RunStreaming executes the command and streams output lines in the background.
+// Returns a StreamingResult that can be polled for updates.
+// The command runs until ctx is cancelled or it completes naturally.
+// If prevLines is provided, lines are updated in place rather than starting fresh.
+func (r *Runner) RunStreaming(ctx context.Context, prevLines []Line) *StreamingResult {
+	// Copy previous lines to allow in-place updates
+	lines := make([]Line, len(prevLines))
+	copy(lines, prevLines)
+
+	result := &StreamingResult{
+		Lines:         &lines,
+		ExitCode:      -1,
+		Done:          false,
+		PrevLineCount: len(prevLines),
 	}
 
-	stderr, err := cmd.StderrPipe()
-	if err != nil {
-		return fmt.Errorf("failed to create stderr pipe: %w", err)
-	}
+	go func() {
+		args := r.buildCommand()
+		cmd := exec.CommandContext(ctx, r.Shell, args...)
+		cmd.Env = append(os.Environ(), "WATCHR=1")
 
-	if err := cmd.Start(); err != nil {
-		return fmt.Errorf("failed to start command: %w", err)
-	}
-
-	lineNum := 1
-
-	// Read from both stdout and stderr concurrently
-	var wg sync.WaitGroup
-	wg.Add(2)
-
-	readPipe := func(pipe io.Reader) {
-		defer wg.Done()
-		scanner := bufio.NewScanner(pipe)
-		for scanner.Scan() {
-			mu.Lock()
-			*lines = append(*lines, Line{
-				Number:  lineNum,
-				Content: scanner.Text(),
-			})
-			lineNum++
-			mu.Unlock()
+		stdout, err := cmd.StdoutPipe()
+		if err != nil {
+			result.mu.Lock()
+			result.Error = fmt.Errorf("failed to create stdout pipe: %w", err)
+			result.Done = true
+			result.mu.Unlock()
+			return
 		}
-	}
 
-	go readPipe(stdout)
-	go readPipe(stderr)
+		stderr, err := cmd.StderrPipe()
+		if err != nil {
+			result.mu.Lock()
+			result.Error = fmt.Errorf("failed to create stderr pipe: %w", err)
+			result.Done = true
+			result.mu.Unlock()
+			return
+		}
 
-	wg.Wait()
+		if err := cmd.Start(); err != nil {
+			result.mu.Lock()
+			result.Error = fmt.Errorf("failed to start command: %w", err)
+			result.Done = true
+			result.mu.Unlock()
+			return
+		}
 
-	// Wait for command to finish (ignore exit code - we still want to show output)
-	_ = cmd.Wait()
+		lineNum := 1
+		var lineNumMu sync.Mutex
 
-	return nil
+		// Read from both stdout and stderr concurrently
+		var wg sync.WaitGroup
+		wg.Add(2)
+
+		readPipe := func(pipe io.Reader) {
+			defer wg.Done()
+			scanner := bufio.NewScanner(pipe)
+			for scanner.Scan() {
+				lineNumMu.Lock()
+				currentLineNum := lineNum
+				lineIdx := lineNum - 1 // 0-indexed
+				lineNum++
+				lineNumMu.Unlock()
+
+				newLine := Line{
+					Number:  currentLineNum,
+					Content: sanitizeLine(scanner.Text()),
+				}
+
+				result.mu.Lock()
+				if lineIdx < len(*result.Lines) {
+					// Update existing line in place
+					(*result.Lines)[lineIdx] = newLine
+				} else {
+					// Append new line
+					*result.Lines = append(*result.Lines, newLine)
+				}
+				// Track how many lines this run has produced
+				if currentLineNum > result.CurrentLineCount {
+					result.CurrentLineCount = currentLineNum
+				}
+				result.mu.Unlock()
+			}
+		}
+
+		go readPipe(stdout)
+		go readPipe(stderr)
+
+		wg.Wait()
+
+		// Wait for command to finish and get exit code
+		exitCode := 0
+		if err := cmd.Wait(); err != nil {
+			if exitErr, ok := err.(*exec.ExitError); ok {
+				exitCode = exitErr.ExitCode()
+			} else if ctx.Err() != nil {
+				// Context was cancelled
+				exitCode = -1
+			}
+		}
+
+		result.mu.Lock()
+		result.ExitCode = exitCode
+		result.Done = true
+		result.mu.Unlock()
+	}()
+
+	return result
 }
 
 // RunSimple executes the command and returns output as string slice
 func (r *Runner) RunSimple(ctx context.Context) ([]string, error) {
-	cmd := exec.CommandContext(ctx, r.Shell, "-c", r.Command)
+	args := r.buildCommand()
+	cmd := exec.CommandContext(ctx, r.Shell, args...)
+	cmd.Env = append(os.Environ(), "WATCHR=1")
 	output, err := cmd.CombinedOutput()
 	if err != nil {
 		// Still return output even on error (non-zero exit)

internal/runner/runner_test.go

@@ -14,6 +14,97 @@ func TestNewRunner(t *testing.T) {
 	if r.Command != "echo hello" {
 		t.Errorf("expected command 'echo hello', got %q", r.Command)
 	}
+	if r.Interactive {
+		t.Errorf("expected Interactive to be false for NewRunner")
+	}
+}
+
+func TestNewInteractiveRunner(t *testing.T) {
+	r := NewInteractiveRunner("bash", "my_func")
+	if r.Shell != "bash" {
+		t.Errorf("expected shell 'bash', got %q", r.Shell)
+	}
+	if r.Command != "my_func" {
+		t.Errorf("expected command 'my_func', got %q", r.Command)
+	}
+	if !r.Interactive {
+		t.Errorf("expected Interactive to be true for NewInteractiveRunner")
+	}
+}
+
+func TestRunner_buildCommand(t *testing.T) {
+	tests := []struct {
+		name        string
+		shell       string
+		command     string
+		interactive bool
+		wantFirst   string
+	}{
+		{
+			name:        "non-interactive",
+			shell:       "sh",
+			command:     "echo hello",
+			interactive: false,
+			wantFirst:   "-c",
+		},
+		{
+			name:        "interactive bash",
+			shell:       "bash",
+			command:     "my_func",
+			interactive: true,
+			wantFirst:   "-c",
+		},
+		{
+			name:        "interactive zsh",
+			shell:       "/bin/zsh",
+			command:     "my_alias",
+			interactive: true,
+			wantFirst:   "-c",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var r *Runner
+			if tt.interactive {
+				r = NewInteractiveRunner(tt.shell, tt.command)
+			} else {
+				r = NewRunner(tt.shell, tt.command)
+			}
+
+			args := r.buildCommand()
+			if len(args) != 2 {
+				t.Fatalf("expected 2 args, got %d", len(args))
+			}
+			if args[0] != tt.wantFirst {
+				t.Errorf("expected first arg %q, got %q", tt.wantFirst, args[0])
+			}
+
+			// For interactive mode, the command should contain sourcing logic
+			if tt.interactive {
+				if !contains(args[1], tt.command) {
+					t.Errorf("expected command %q to be in args[1] %q", tt.command, args[1])
+				}
+			} else {
+				if args[1] != tt.command {
+					t.Errorf("expected args[1] to be %q, got %q", tt.command, args[1])
+				}
+			}
+		})
+	}
+}
+
+func contains(s, substr string) bool {
+	return len(s) >= len(substr) && (s == substr || len(s) > 0 && containsHelper(s, substr))
+}
+
+func containsHelper(s, substr string) bool {
+	for i := 0; i <= len(s)-len(substr); i++ {
+		if s[i:i+len(substr)] == substr {
+			return true
+		}
+	}
+	return false
 }
 
 func TestRunner_Run(t *testing.T) {
@@ -229,3 +320,205 @@ func TestSplitLines(t *testing.T) {
 		})
 	}
 }
+
+func TestSanitizeLine(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{
+			name:  "plain text unchanged",
+			input: "hello world",
+			want:  "hello world",
+		},
+		{
+			name:  "tabs converted to spaces",
+			input: "col1\tcol2\tcol3",
+			want:  "col1        col2        col3",
+		},
+		{
+			name:  "carriage returns removed",
+			input: "line with\r\nwindows ending",
+			want:  "line with\nwindows ending",
+		},
+		{
+			name:  "carriage return only removed",
+			input: "progress\roverwrite",
+			want:  "progressoverwrite",
+		},
+		{
+			name:  "ANSI color codes preserved",
+			input: "\x1b[32mgreen text\x1b[0m",
+			want:  "\x1b[32mgreen text\x1b[0m",
+		},
+		{
+			name:  "mixed tabs and colors",
+			input: "\x1b[1m?\x1b[0m\tpackage\t[no test files]",
+			want:  "\x1b[1m?\x1b[0m        package        [no test files]",
+		},
+		{
+			name:  "empty string",
+			input: "",
+			want:  "",
+		},
+		{
+			name:  "multiple tabs",
+			input: "\t\t\t",
+			want:  "                        ",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := sanitizeLine(tt.input)
+			if got != tt.want {
+				t.Errorf("sanitizeLine(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestRunStreaming(t *testing.T) {
+	r := NewRunner("sh", "echo 'line1'; echo 'line2'; echo 'line3'")
+	ctx := context.Background()
+
+	result := r.RunStreaming(ctx, nil)
+
+	// Wait for completion
+	for !result.IsDone() {
+		time.Sleep(10 * time.Millisecond)
+	}
+
+	lines := result.GetLines()
+	if len(lines) != 3 {
+		t.Fatalf("expected 3 lines, got %d", len(lines))
+	}
+
+	if lines[0].Content != "line1" {
+		t.Errorf("expected first line 'line1', got %q", lines[0].Content)
+	}
+
+	if result.GetCurrentLineCount() != 3 {
+		t.Errorf("expected CurrentLineCount 3, got %d", result.GetCurrentLineCount())
+	}
+}
+
+func TestRunStreamingWithPreviousLines(t *testing.T) {
+	// Previous lines that should be overwritten
+	prevLines := []Line{
+		{Number: 1, Content: "old1"},
+		{Number: 2, Content: "old2"},
+		{Number: 3, Content: "old3"},
+		{Number: 4, Content: "old4"},
+		{Number: 5, Content: "old5"},
+	}
+
+	r := NewRunner("sh", "echo 'new1'; echo 'new2'; echo 'new3'")
+	ctx := context.Background()
+
+	result := r.RunStreaming(ctx, prevLines)
+
+	// Verify PrevLineCount is set
+	if result.PrevLineCount != 5 {
+		t.Errorf("expected PrevLineCount 5, got %d", result.PrevLineCount)
+	}
+
+	// Wait for completion
+	for !result.IsDone() {
+		time.Sleep(10 * time.Millisecond)
+	}
+
+	lines := result.GetLines()
+
+	// Should still have 5 lines (3 new + 2 old remaining)
+	if len(lines) != 5 {
+		t.Fatalf("expected 5 lines (in-place update), got %d", len(lines))
+	}
+
+	// First 3 lines should be overwritten
+	if lines[0].Content != "new1" {
+		t.Errorf("expected line 0 'new1', got %q", lines[0].Content)
+	}
+	if lines[1].Content != "new2" {
+		t.Errorf("expected line 1 'new2', got %q", lines[1].Content)
+	}
+	if lines[2].Content != "new3" {
+		t.Errorf("expected line 2 'new3', got %q", lines[2].Content)
+	}
+
+	// Remaining lines should be old (not touched)
+	if lines[3].Content != "old4" {
+		t.Errorf("expected line 3 'old4', got %q", lines[3].Content)
+	}
+	if lines[4].Content != "old5" {
+		t.Errorf("expected line 4 'old5', got %q", lines[4].Content)
+	}
+
+	// CurrentLineCount should be 3 (only new lines written)
+	if result.GetCurrentLineCount() != 3 {
+		t.Errorf("expected CurrentLineCount 3, got %d", result.GetCurrentLineCount())
+	}
+}
+
+func TestRunStreamingMoreLinesThanPrevious(t *testing.T) {
+	// Previous lines (fewer than new output)
+	prevLines := []Line{
+		{Number: 1, Content: "old1"},
+		{Number: 2, Content: "old2"},
+	}
+
+	r := NewRunner("sh", "echo 'new1'; echo 'new2'; echo 'new3'; echo 'new4'")
+	ctx := context.Background()
+
+	result := r.RunStreaming(ctx, prevLines)
+
+	// Wait for completion
+	for !result.IsDone() {
+		time.Sleep(10 * time.Millisecond)
+	}
+
+	lines := result.GetLines()
+
+	// Should have 4 lines (2 overwritten + 2 appended)
+	if len(lines) != 4 {
+		t.Fatalf("expected 4 lines, got %d", len(lines))
+	}
+
+	// All lines should be new
+	for i, expected := range []string{"new1", "new2", "new3", "new4"} {
+		if lines[i].Content != expected {
+			t.Errorf("expected line %d %q, got %q", i, expected, lines[i].Content)
+		}
+	}
+
+	if result.GetCurrentLineCount() != 4 {
+		t.Errorf("expected CurrentLineCount 4, got %d", result.GetCurrentLineCount())
+	}
+}
+
+func TestStreamingResultThreadSafety(t *testing.T) {
+	r := NewRunner("sh", "for i in $(seq 1 100); do echo line$i; done")
+	ctx := context.Background()
+
+	result := r.RunStreaming(ctx, nil)
+
+	// Concurrently read while streaming
+	done := make(chan bool)
+	go func() {
+		for !result.IsDone() {
+			_ = result.GetLines()
+			_ = result.LineCount()
+			_ = result.GetCurrentLineCount()
+			time.Sleep(5 * time.Millisecond)
+		}
+		done <- true
+	}()
+
+	<-done
+
+	// Should complete without race conditions
+	if result.LineCount() != 100 {
+		t.Errorf("expected 100 lines, got %d", result.LineCount())
+	}
+}

internal/ui/highlight.go

@@ -0,0 +1,97 @@
+package ui
+
+import (
+	"bytes"
+	"encoding/json"
+	"regexp"
+	"strings"
+
+	"github.com/alecthomas/chroma/v2"
+	"github.com/alecthomas/chroma/v2/formatters"
+	"github.com/alecthomas/chroma/v2/lexers"
+	"github.com/alecthomas/chroma/v2/styles"
+)
+
+// ansiEscPattern matches ANSI escape sequences (CSI and simple ESC sequences).
+var ansiEscPattern = regexp.MustCompile(`\x1b\[[0-9;?]*[a-zA-Z]|\x1b[^\[]`)
+
+// stripANSI removes all ANSI escape sequences from a string.
+func stripANSI(s string) string {
+	return ansiEscPattern.ReplaceAllString(s, "")
+}
+
+// extractJSON finds the first JSON object or array in a string,
+// skipping any leading non-JSON content (e.g. ANSI codes, log prefixes).
+// Returns the JSON substring and any prefix before it.
+func extractJSON(s string) (prefix, jsonStr string, ok bool) {
+	// Find first { or [
+	idx := strings.IndexAny(s, "{[")
+	if idx < 0 {
+		return "", "", false
+	}
+	return s[:idx], s[idx:], true
+}
+
+// highlightJSON attempts to detect JSON content, pretty-print it, and apply
+// syntax highlighting for terminal output. Returns the original string
+// unchanged if the content is not valid JSON.
+func highlightJSON(s string) string {
+	trimmed := strings.TrimSpace(s)
+	if len(trimmed) == 0 {
+		return s
+	}
+
+	// Strip ANSI codes for JSON detection and parsing
+	clean := stripANSI(trimmed)
+
+	// Extract JSON from the string (may have a non-JSON prefix)
+	prefix, jsonStr, ok := extractJSON(clean)
+	if !ok {
+		return s
+	}
+
+	// Try to pretty-print the JSON portion
+	var buf bytes.Buffer
+	if err := json.Indent(&buf, []byte(jsonStr), "", "  "); err != nil {
+		return s
+	}
+	pretty := buf.String()
+
+	// Highlight with chroma (only the JSON portion)
+	lexer := lexers.Get("json")
+	if lexer == nil {
+		return pretty
+	}
+	lexer = chroma.Coalesce(lexer)
+
+	style := styles.Get("monokai")
+	if style == nil {
+		style = styles.Fallback
+	}
+
+	formatter := formatters.Get("terminal256")
+	if formatter == nil {
+		formatter = formatters.Fallback
+	}
+
+	iterator, err := lexer.Tokenise(nil, pretty)
+	if err != nil {
+		return pretty
+	}
+
+	var out bytes.Buffer
+	if err := formatter.Format(&out, style, iterator); err != nil {
+		return pretty
+	}
+
+	// Re-attach any non-JSON prefix (stripped of ANSI)
+	result := out.String()
+	if prefix != "" {
+		prefix = strings.TrimSpace(prefix)
+		if prefix != "" {
+			result = prefix + "\n" + result
+		}
+	}
+
+	return result
+}

internal/ui/highlight_test.go

@@ -0,0 +1,164 @@
+package ui
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestWrapTextANSI(t *testing.T) {
+	t.Run("ANSI sequences are not split", func(t *testing.T) {
+		// Red "ab" then reset: \033[31mab\033[0m
+		input := "\033[31mabcdef\033[0m"
+		lines := wrapText(input, 3)
+		// Should wrap into "abc" and "def", each with proper ANSI
+		if len(lines) != 2 {
+			t.Fatalf("expected 2 lines, got %d: %q", len(lines), lines)
+		}
+		// First line should have the color and a reset
+		if !strings.Contains(lines[0], "\033[31m") {
+			t.Errorf("first line missing color code: %q", lines[0])
+		}
+		if !strings.Contains(lines[0], "abc") {
+			t.Errorf("first line missing 'abc': %q", lines[0])
+		}
+		// Second line should re-apply the color
+		if !strings.Contains(lines[1], "\033[31m") {
+			t.Errorf("second line missing re-applied color code: %q", lines[1])
+		}
+		if !strings.Contains(lines[1], "def") {
+			t.Errorf("second line missing 'def': %q", lines[1])
+		}
+	})
+
+	t.Run("no ANSI still works", func(t *testing.T) {
+		lines := wrapText("abcdef", 3)
+		if len(lines) != 2 {
+			t.Fatalf("expected 2 lines, got %d", len(lines))
+		}
+		if lines[0] != "abc" {
+			t.Errorf("expected 'abc', got %q", lines[0])
+		}
+		if lines[1] != "def" {
+			t.Errorf("expected 'def', got %q", lines[1])
+		}
+	})
+
+	t.Run("ANSI reset clears active state", func(t *testing.T) {
+		// Color "ab", reset, then "cd"
+		input := "\033[31mab\033[0mcd"
+		lines := wrapText(input, 2)
+		// "ab" on first line (with color), "cd" on second (no color re-applied)
+		if len(lines) != 2 {
+			t.Fatalf("expected 2 lines, got %d: %q", len(lines), lines)
+		}
+		// Second line should NOT have the red color re-applied
+		if strings.Contains(lines[1], "\033[31m") {
+			t.Errorf("second line should not have color after reset: %q", lines[1])
+		}
+	})
+}
+
+func TestWrapPreviewContentANSI(t *testing.T) {
+	// Multi-line input with ANSI codes should survive split + wrap
+	input := "\033[31mhello\033[0m\n\033[32mworld\033[0m"
+	lines := wrapPreviewContent(input, 80)
+	if len(lines) != 2 {
+		t.Fatalf("expected 2 lines, got %d", len(lines))
+	}
+	if !strings.Contains(lines[0], "\033[31m") || !strings.Contains(lines[0], "hello") {
+		t.Errorf("first line missing color or content: %q", lines[0])
+	}
+	if !strings.Contains(lines[1], "\033[32m") || !strings.Contains(lines[1], "world") {
+		t.Errorf("second line missing color or content: %q", lines[1])
+	}
+}
+
+func TestHighlightJSON(t *testing.T) {
+	t.Run("valid JSON object is pretty-printed and highlighted", func(t *testing.T) {
+		input := `{"name":"test","count":42}`
+		result := highlightJSON(input)
+
+		// Should be pretty-printed (multi-line)
+		if !strings.Contains(result, "\n") {
+			t.Error("expected multi-line pretty-printed output")
+		}
+		// Should contain the key and value
+		if !strings.Contains(result, "name") {
+			t.Error("expected output to contain 'name'")
+		}
+		if !strings.Contains(result, "test") {
+			t.Error("expected output to contain 'test'")
+		}
+		if !strings.Contains(result, "42") {
+			t.Error("expected output to contain '42'")
+		}
+		// Should contain ANSI escape codes (syntax highlighting)
+		if !strings.Contains(result, "\033[") {
+			t.Error("expected ANSI color codes in output")
+		}
+	})
+
+	t.Run("valid JSON array", func(t *testing.T) {
+		input := `[1, 2, 3]`
+		result := highlightJSON(input)
+		if !strings.Contains(result, "\033[") {
+			t.Error("expected ANSI color codes for JSON array")
+		}
+	})
+
+	t.Run("non-JSON returns unchanged", func(t *testing.T) {
+		input := "hello world"
+		result := highlightJSON(input)
+		if result != input {
+			t.Errorf("expected unchanged output for non-JSON, got %q", result)
+		}
+	})
+
+	t.Run("invalid JSON returns unchanged", func(t *testing.T) {
+		input := `{"broken": }`
+		result := highlightJSON(input)
+		if result != input {
+			t.Errorf("expected unchanged output for invalid JSON, got %q", result)
+		}
+	})
+
+	t.Run("empty string returns unchanged", func(t *testing.T) {
+		result := highlightJSON("")
+		if result != "" {
+			t.Errorf("expected empty string, got %q", result)
+		}
+	})
+
+	t.Run("whitespace-only returns unchanged", func(t *testing.T) {
+		input := "   "
+		result := highlightJSON(input)
+		if result != input {
+			t.Errorf("expected unchanged output, got %q", result)
+		}
+	})
+
+	t.Run("JSON with leading ANSI escape sequences", func(t *testing.T) {
+		input := "\x1b[34h\x1b[?25h{\"key\":\"value\"}"
+		result := highlightJSON(input)
+		if !strings.Contains(result, "key") {
+			t.Error("expected output to contain 'key'")
+		}
+		if !strings.Contains(result, "value") {
+			t.Error("expected output to contain 'value'")
+		}
+		if !strings.Contains(result, "\033[") {
+			t.Error("expected ANSI color codes in output")
+		}
+	})
+
+	t.Run("JSON with non-JSON prefix text", func(t *testing.T) {
+		input := `some prefix {"key":"value"}`
+		result := highlightJSON(input)
+		if !strings.Contains(result, "key") {
+			t.Error("expected output to contain 'key'")
+		}
+		if !strings.Contains(result, "some prefix") {
+			t.Error("expected output to preserve prefix")
+		}
+	})
+}

internal/ui/ui_test.go

@@ -1,8 +1,11 @@
 package ui
 
 import (
+	"context"
 	"testing"
+	"time"
 
+	tea "github.com/charmbracelet/bubbletea"
 	"github.com/chenasraf/watchr/internal/runner"
 )
 
@@ -16,7 +19,7 @@ func TestConfig(t *testing.T) {
 		ShowLineNums:         true,
 		LineNumWidth:         6,
 		Prompt:               "watchr> ",
-		RefreshSeconds:       5,
+		RefreshInterval:      5 * time.Second,
 	}
 
 	if cfg.Command != "echo test" {
@@ -51,8 +54,8 @@ func TestConfig(t *testing.T) {
 		t.Errorf("expected prompt 'watchr> ', got %q", cfg.Prompt)
 	}
 
-	if cfg.RefreshSeconds != 5 {
-		t.Errorf("expected refresh seconds 5, got %d", cfg.RefreshSeconds)
+	if cfg.RefreshInterval != 5*time.Second {
+		t.Errorf("expected refresh interval 5s, got %v", cfg.RefreshInterval)
 	}
 }
 
@@ -283,3 +286,575 @@ func TestVisibleLines(t *testing.T) {
 		t.Errorf("expected %d visible lines with absolute preview size, got %d", expected, visible)
 	}
 }
+
+func TestUpdateFilteredPreservesOffset(t *testing.T) {
+	cfg := Config{
+		Command: "echo test",
+		Shell:   "sh",
+	}
+
+	m := initialModel(cfg)
+	m.height = 20 // Enough for visibleLines to return > 0
+
+	// Add many test lines
+	for i := 1; i <= 100; i++ {
+		m.lines = append(m.lines, runner.Line{Number: i, Content: "line content"})
+	}
+
+	// Set initial state with offset
+	m.filter = ""
+	m.updateFiltered()
+	m.offset = 50
+	m.cursor = 55
+
+	// Simulate streaming update - add more lines without changing filter
+	m.lines = append(m.lines, runner.Line{Number: 101, Content: "new line"})
+	m.updateFiltered()
+
+	// Offset should be preserved (or clamped if necessary)
+	if m.offset < 50 {
+		t.Errorf("expected offset to be preserved (>= 50), got %d", m.offset)
+	}
+
+	// Cursor should be preserved
+	if m.cursor != 55 {
+		t.Errorf("expected cursor to be preserved at 55, got %d", m.cursor)
+	}
+}
+
+func TestUpdateFilteredClampsOffsetWhenNeeded(t *testing.T) {
+	cfg := Config{
+		Command: "echo test",
+		Shell:   "sh",
+	}
+
+	m := initialModel(cfg)
+	m.height = 20
+
+	// Add test lines
+	for i := 1; i <= 100; i++ {
+		m.lines = append(m.lines, runner.Line{Number: i, Content: "line content"})
+	}
+
+	m.filter = ""
+	m.updateFiltered()
+	m.offset = 90
+	m.cursor = 95
+
+	// Now filter to fewer lines
+	m.filter = "xyz" // No matches
+	m.updateFiltered()
+
+	// Offset should be clamped to valid range
+	if m.offset != 0 {
+		t.Errorf("expected offset to be clamped to 0, got %d", m.offset)
+	}
+
+	// Cursor should be clamped
+	if m.cursor != 0 {
+		t.Errorf("expected cursor to be clamped to 0, got %d", m.cursor)
+	}
+}
+
+func TestConfigRefreshFromStart(t *testing.T) {
+	// Test with RefreshFromStart false (default)
+	cfg := Config{
+		Command:          "echo test",
+		Shell:            "sh",
+		RefreshInterval:  5 * time.Second,
+		RefreshFromStart: false,
+	}
+
+	if cfg.RefreshFromStart {
+		t.Error("expected RefreshFromStart to be false by default")
+	}
+
+	// Test with RefreshFromStart true
+	cfg.RefreshFromStart = true
+	if !cfg.RefreshFromStart {
+		t.Error("expected RefreshFromStart to be true after setting")
+	}
+}
+
+func TestModelUserScrolled(t *testing.T) {
+	cfg := Config{
+		Command: "echo test",
+		Shell:   "sh",
+	}
+
+	m := initialModel(cfg)
+
+	// Initially should be false
+	if m.userScrolled {
+		t.Error("expected userScrolled to be false initially")
+	}
+
+	// After setting, should be true
+	m.userScrolled = true
+	if !m.userScrolled {
+		t.Error("expected userScrolled to be true after setting")
+	}
+}
+
+func TestModelRefreshGeneration(t *testing.T) {
+	cfg := Config{
+		Command: "echo test",
+		Shell:   "sh",
+	}
+
+	m := initialModel(cfg)
+
+	// Initially should be 0
+	if m.refreshGeneration != 0 {
+		t.Errorf("expected refreshGeneration to be 0 initially, got %d", m.refreshGeneration)
+	}
+
+	// After incrementing
+	m.refreshGeneration++
+	if m.refreshGeneration != 1 {
+		t.Errorf("expected refreshGeneration to be 1 after increment, got %d", m.refreshGeneration)
+	}
+}
+
+func testModel(cfg Config) *model {
+	m := initialModel(cfg)
+	return &m
+}
+
+func TestFilterCursorMovement(t *testing.T) {
+	cfg := Config{Command: "echo test", Shell: "sh"}
+	m := testModel(cfg)
+	m.filterMode = true
+	m.filter = "hello"
+	m.filterCursor = 5
+
+	// Left arrow moves cursor left
+	keyMsg := tea.KeyMsg{Type: tea.KeyLeft}
+	result, _ := m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if m.filterCursor != 4 {
+		t.Errorf("expected filterCursor 4 after left, got %d", m.filterCursor)
+	}
+
+	// Left again
+	result, _ = m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if m.filterCursor != 3 {
+		t.Errorf("expected filterCursor 3 after second left, got %d", m.filterCursor)
+	}
+
+	// Left doesn't go below 0
+	m.filterCursor = 0
+	result, _ = m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if m.filterCursor != 0 {
+		t.Errorf("expected filterCursor 0 (clamped), got %d", m.filterCursor)
+	}
+
+	// Right arrow moves cursor right
+	m.filterCursor = 2
+	keyMsg = tea.KeyMsg{Type: tea.KeyRight}
+	result, _ = m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if m.filterCursor != 3 {
+		t.Errorf("expected filterCursor 3 after right, got %d", m.filterCursor)
+	}
+
+	// Right doesn't go past end
+	m.filterCursor = 5
+	result, _ = m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if m.filterCursor != 5 {
+		t.Errorf("expected filterCursor 5 (clamped), got %d", m.filterCursor)
+	}
+}
+
+func TestFilterAltLeftRight(t *testing.T) {
+	cfg := Config{Command: "echo test", Shell: "sh"}
+
+	t.Run("alt+left jumps to previous word boundary", func(t *testing.T) {
+		m := testModel(cfg)
+		m.filterMode = true
+		m.filter = "foo bar baz"
+		m.filterCursor = 11 // end
+
+		keyMsg := tea.KeyMsg{Type: tea.KeyLeft, Alt: true}
+		result, _ := m.handleKeyPress(keyMsg)
+		m = result.(*model)
+		if m.filterCursor != 8 {
+			t.Errorf("expected filterCursor 8, got %d", m.filterCursor)
+		}
+
+		result, _ = m.handleKeyPress(keyMsg)
+		m = result.(*model)
+		if m.filterCursor != 4 {
+			t.Errorf("expected filterCursor 4, got %d", m.filterCursor)
+		}
+
+		result, _ = m.handleKeyPress(keyMsg)
+		m = result.(*model)
+		if m.filterCursor != 0 {
+			t.Errorf("expected filterCursor 0, got %d", m.filterCursor)
+		}
+
+		// Already at start, stays at 0
+		result, _ = m.handleKeyPress(keyMsg)
+		m = result.(*model)
+		if m.filterCursor != 0 {
+			t.Errorf("expected filterCursor 0 (clamped), got %d", m.filterCursor)
+		}
+	})
+
+	t.Run("alt+right jumps to next word boundary", func(t *testing.T) {
+		m := testModel(cfg)
+		m.filterMode = true
+		m.filter = "foo bar baz"
+		m.filterCursor = 0
+
+		keyMsg := tea.KeyMsg{Type: tea.KeyRight, Alt: true}
+		result, _ := m.handleKeyPress(keyMsg)
+		m = result.(*model)
+		if m.filterCursor != 4 {
+			t.Errorf("expected filterCursor 4, got %d", m.filterCursor)
+		}
+
+		result, _ = m.handleKeyPress(keyMsg)
+		m = result.(*model)
+		if m.filterCursor != 8 {
+			t.Errorf("expected filterCursor 8, got %d", m.filterCursor)
+		}
+
+		result, _ = m.handleKeyPress(keyMsg)
+		m = result.(*model)
+		if m.filterCursor != 11 {
+			t.Errorf("expected filterCursor 11, got %d", m.filterCursor)
+		}
+
+		// Already at end, stays at 11
+		result, _ = m.handleKeyPress(keyMsg)
+		m = result.(*model)
+		if m.filterCursor != 11 {
+			t.Errorf("expected filterCursor 11 (clamped), got %d", m.filterCursor)
+		}
+	})
+
+	t.Run("alt+left skips trailing spaces", func(t *testing.T) {
+		m := testModel(cfg)
+		m.filterMode = true
+		m.filter = "foo   bar"
+		m.filterCursor = 6 // middle of spaces, before "bar"
+
+		keyMsg := tea.KeyMsg{Type: tea.KeyLeft, Alt: true}
+		result, _ := m.handleKeyPress(keyMsg)
+		m = result.(*model)
+		if m.filterCursor != 0 {
+			t.Errorf("expected filterCursor 0, got %d", m.filterCursor)
+		}
+	})
+
+	t.Run("alt+right skips trailing spaces", func(t *testing.T) {
+		m := testModel(cfg)
+		m.filterMode = true
+		m.filter = "foo   bar"
+		m.filterCursor = 3 // end of "foo"
+
+		keyMsg := tea.KeyMsg{Type: tea.KeyRight, Alt: true}
+		result, _ := m.handleKeyPress(keyMsg)
+		m = result.(*model)
+		if m.filterCursor != 6 {
+			t.Errorf("expected filterCursor 6, got %d", m.filterCursor)
+		}
+	})
+}
+
+func TestFilterInsertAtCursor(t *testing.T) {
+	cfg := Config{Command: "echo test", Shell: "sh"}
+	m := testModel(cfg)
+	m.filterMode = true
+	m.filter = "helo"
+	m.filterCursor = 3
+
+	// Insert 'l' at position 3 -> "hello"
+	keyMsg := tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'l'}}
+	result, _ := m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if m.filter != "hello" {
+		t.Errorf("expected filter 'hello', got %q", m.filter)
+	}
+	if m.filterCursor != 4 {
+		t.Errorf("expected filterCursor 4, got %d", m.filterCursor)
+	}
+}
+
+func TestFilterBackspaceAtCursor(t *testing.T) {
+	cfg := Config{Command: "echo test", Shell: "sh"}
+	m := testModel(cfg)
+	m.filterMode = true
+	m.filter = "hello"
+	m.filterCursor = 3
+
+	// Backspace at position 3 -> "helo"
+	keyMsg := tea.KeyMsg{Type: tea.KeyBackspace}
+	result, _ := m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if m.filter != "helo" {
+		t.Errorf("expected filter 'helo', got %q", m.filter)
+	}
+	if m.filterCursor != 2 {
+		t.Errorf("expected filterCursor 2, got %d", m.filterCursor)
+	}
+
+	// Backspace at position 0 does nothing
+	m.filterCursor = 0
+	result, _ = m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if m.filter != "helo" {
+		t.Errorf("expected filter 'helo' (unchanged), got %q", m.filter)
+	}
+	if m.filterCursor != 0 {
+		t.Errorf("expected filterCursor 0, got %d", m.filterCursor)
+	}
+}
+
+func TestFilterAltBackspace(t *testing.T) {
+	cfg := Config{Command: "echo test", Shell: "sh"}
+
+	tests := []struct {
+		name           string
+		filter         string
+		cursor         int
+		expectedFilter string
+		expectedCursor int
+	}{
+		{"delete last word", "hello world", 11, "hello ", 6},
+		{"delete middle word", "foo bar baz", 7, "foo  baz", 4},
+		{"delete first word", "hello world", 5, " world", 0},
+		{"delete with trailing spaces", "hello   ", 8, "", 0},
+		{"cursor at start", "hello", 0, "hello", 0},
+		{"single word", "hello", 5, "", 0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			m := testModel(cfg)
+			m.filterMode = true
+			m.filter = tt.filter
+			m.filterCursor = tt.cursor
+
+			keyMsg := tea.KeyMsg{Type: tea.KeyBackspace, Alt: true}
+			result, _ := m.handleKeyPress(keyMsg)
+			newModel := result.(*model)
+
+			if newModel.filter != tt.expectedFilter {
+				t.Errorf("expected filter %q, got %q", tt.expectedFilter, newModel.filter)
+			}
+			if newModel.filterCursor != tt.expectedCursor {
+				t.Errorf("expected filterCursor %d, got %d", tt.expectedCursor, newModel.filterCursor)
+			}
+		})
+	}
+}
+
+func TestFilterRegexToggle(t *testing.T) {
+	cfg := Config{Command: "echo test", Shell: "sh"}
+	m := testModel(cfg)
+	m.filterMode = true
+	m.filter = ""
+	m.filterCursor = 0
+
+	// Type '/' on empty filter toggles regex mode on
+	keyMsg := tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'/'}}
+	result, _ := m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if !m.filterRegex {
+		t.Error("expected filterRegex to be true after typing /")
+	}
+	if m.filter != "" {
+		t.Errorf("expected empty filter, got %q", m.filter)
+	}
+
+	// Type '/' again on empty filter toggles regex mode off
+	result, _ = m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if m.filterRegex {
+		t.Error("expected filterRegex to be false after second /")
+	}
+
+	// Type '/' when filter is non-empty adds it to filter
+	m.filterRegex = true
+	m.filter = "abc"
+	m.filterCursor = 3
+	result, _ = m.handleKeyPress(keyMsg)
+	m = result.(*model)
+	if m.filter != "abc/" {
+		t.Errorf("expected filter 'abc/', got %q", m.filter)
+	}
+	if !m.filterRegex {
+		t.Error("expected filterRegex to remain true")
+	}
+}
+
+func TestFilterRegexMatching(t *testing.T) {
+	cfg := Config{Command: "echo test", Shell: "sh"}
+	m := initialModel(cfg)
+	m.lines = []runner.Line{
+		{Number: 1, Content: "hello world"},
+		{Number: 2, Content: "foo bar"},
+		{Number: 3, Content: "hello foo"},
+		{Number: 4, Content: "baz 123 qux"},
+	}
+
+	// Regex filter matching
+	m.filterRegex = true
+	m.filter = "hello.*foo"
+	m.updateFiltered()
+	if len(m.filtered) != 1 {
+		t.Errorf("expected 1 match for regex 'hello.*foo', got %d", len(m.filtered))
+	}
+	if len(m.filtered) > 0 && m.filtered[0] != 2 {
+		t.Errorf("expected match at index 2, got %d", m.filtered[0])
+	}
+
+	// Regex with character class
+	m.filter = "\\d+"
+	m.updateFiltered()
+	if len(m.filtered) != 1 {
+		t.Errorf("expected 1 match for regex '\\d+', got %d", len(m.filtered))
+	}
+
+	// Regex is case insensitive
+	m.filter = "HELLO"
+	m.updateFiltered()
+	if len(m.filtered) != 2 {
+		t.Errorf("expected 2 matches for case-insensitive regex 'HELLO', got %d", len(m.filtered))
+	}
+}
+
+func TestFilterRegexInvalid(t *testing.T) {
+	cfg := Config{Command: "echo test", Shell: "sh"}
+	m := initialModel(cfg)
+	m.lines = []runner.Line{
+		{Number: 1, Content: "hello world"},
+		{Number: 2, Content: "foo bar"},
+	}
+
+	m.filterRegex = true
+	m.filter = "[invalid"
+	m.updateFiltered()
+
+	// Should have an error
+	if m.filterRegexErr == nil {
+		t.Error("expected filterRegexErr to be non-nil for invalid regex")
+	}
+
+	// Should show all lines when regex is invalid
+	if len(m.filtered) != 2 {
+		t.Errorf("expected all 2 lines shown for invalid regex, got %d", len(m.filtered))
+	}
+
+	// Valid regex clears the error
+	m.filter = "hello"
+	m.updateFiltered()
+	if m.filterRegexErr != nil {
+		t.Errorf("expected filterRegexErr to be nil for valid regex, got %v", m.filterRegexErr)
+	}
+}
+
+func TestFilterEscClearsRegex(t *testing.T) {
+	cfg := Config{Command: "echo test", Shell: "sh"}
+	m := testModel(cfg)
+	m.filterMode = true
+	m.filter = "test"
+	m.filterCursor = 4
+	m.filterRegex = true
+
+	// Esc in filter mode clears everything
+	keyMsg := tea.KeyMsg{Type: tea.KeyEsc}
+	result, _ := m.handleKeyPress(keyMsg)
+	m = result.(*model)
+
+	if m.filterMode {
+		t.Error("expected filterMode to be false")
+	}
+	if m.filter != "" {
+		t.Errorf("expected empty filter, got %q", m.filter)
+	}
+	if m.filterCursor != 0 {
+		t.Errorf("expected filterCursor 0, got %d", m.filterCursor)
+	}
+	if m.filterRegex {
+		t.Error("expected filterRegex to be false")
+	}
+}
+
+func TestStopCommandKeybinding(t *testing.T) {
+	cfg := Config{
+		Command: "echo test",
+		Shell:   "sh",
+	}
+
+	t.Run("stops running command when streaming", func(t *testing.T) {
+		m := initialModel(cfg)
+		// Set up a cancellable context to track if cancel was called
+		ctx, cancel := context.WithCancel(context.Background())
+		m.ctx = ctx
+		m.cancel = cancel
+		m.streaming = true
+		m.statusMsg = ""
+
+		// Simulate pressing 'c'
+		keyMsg := tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'c'}}
+		result, cmd := m.handleKeyPress(keyMsg)
+		newModel := result.(*model)
+
+		// Should set status message
+		if newModel.statusMsg != "Command stopped" {
+			t.Errorf("expected statusMsg 'Command stopped', got %q", newModel.statusMsg)
+		}
+
+		// Should return a command (the tick for clearing status)
+		if cmd == nil {
+			t.Error("expected a command to be returned for status message timeout")
+		}
+
+		// Context should be cancelled
+		select {
+		case <-ctx.Done():
+			// Good, context was cancelled
+		default:
+			t.Error("expected context to be cancelled")
+		}
+	})
+
+	t.Run("does nothing when not streaming", func(t *testing.T) {
+		m := initialModel(cfg)
+		ctx, cancel := context.WithCancel(context.Background())
+		m.ctx = ctx
+		m.cancel = cancel
+		m.streaming = false
+		m.statusMsg = ""
+
+		// Simulate pressing 'c'
+		keyMsg := tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'c'}}
+		result, cmd := m.handleKeyPress(keyMsg)
+		newModel := result.(*model)
+
+		// Should not set status message
+		if newModel.statusMsg != "" {
+			t.Errorf("expected empty statusMsg, got %q", newModel.statusMsg)
+		}
+
+		// Should not return a command
+		if cmd != nil {
+			t.Error("expected no command to be returned when not streaming")
+		}
+
+		// Context should NOT be cancelled
+		select {
+		case <-ctx.Done():
+			t.Error("expected context to NOT be cancelled when not streaming")
+		default:
+			// Good, context is still active
+		}
+	})
+}

main.go

@@ -34,7 +34,9 @@ func main() {
 	flag.IntP("line-width", "w", 6, "Line number width")
 	flag.StringP("prompt", "p", "watchr> ", "Prompt string")
 	flag.StringP("shell", "s", "sh", "Shell to use for executing commands")
-	flag.IntP("refresh", "r", 0, "Auto-refresh interval in seconds (0 = disabled)")
+	flag.StringP("refresh", "r", "0", "Auto-refresh interval (e.g., 1, 1.5, 500ms, 2s, 5m, 1h; default unit: seconds, 0 = disabled)")
+	flag.Bool("refresh-from-start", false, "Start refresh timer when command starts (default: when command ends)")
+	flag.BoolP("interactive", "i", false, "Run shell in interactive mode (sources ~/.bashrc, ~/.zshrc, etc.)")
 
 	printUsage := func(w *os.File) {
 		_, _ = fmt.Fprintf(w, "Usage: watchr [options] <command to run>\n\n")
@@ -45,6 +47,7 @@ func main() {
 		flag.CommandLine.SetOutput(os.Stderr)
 		_, _ = fmt.Fprintf(w, "\nKeybindings:\n")
 		_, _ = fmt.Fprintf(w, "  r, Ctrl-r      Reload (re-run command)\n")
+		_, _ = fmt.Fprintf(w, "  c              Stop running command\n")
 		_, _ = fmt.Fprintf(w, "  q, Esc         Quit\n")
 		_, _ = fmt.Fprintf(w, "  j, k           Move down/up\n")
 		_, _ = fmt.Fprintf(w, "  g              Go to first line\n")
@@ -55,6 +58,7 @@ func main() {
 		_, _ = fmt.Fprintf(w, "  /              Enter filter mode\n")
 		_, _ = fmt.Fprintf(w, "  Esc            Exit filter mode / clear filter\n")
 		_, _ = fmt.Fprintf(w, "  y              Yank (copy) selected line\n")
+		_, _ = fmt.Fprintf(w, "  Y              Yank selected line (plain text)\n")
 		_, _ = fmt.Fprintf(w, "  ?              Show help overlay\n")
 	}
 
@@ -107,8 +111,10 @@ func main() {
 	shell := config.GetString(config.KeyShell)
 	lineNumWidth := config.GetInt(config.KeyLineWidth)
 	prompt := config.GetString(config.KeyPrompt)
-	refreshSeconds := config.GetInt(config.KeyRefresh)
+	refreshInterval := config.GetDuration(config.KeyRefresh)
+	refreshFromStart := config.GetBool(config.KeyRefreshFromStart)
 	showLineNums := config.ShowLineNumbers()
+	interactive := config.GetBool(config.KeyInteractive)
 
 	// Parse preview size (e.g., "40" for lines/cols, "40%" for percentage)
 	previewSizeIsPercent := strings.HasSuffix(previewSize, "%")
@@ -128,7 +134,9 @@ func main() {
 		ShowLineNums:         showLineNums,
 		LineNumWidth:         lineNumWidth,
 		Prompt:               prompt,
-		RefreshSeconds:       refreshSeconds,
+		RefreshInterval:      refreshInterval,
+		RefreshFromStart:     refreshFromStart,
+		Interactive:          interactive,
 	}
 
 	if err := ui.Run(uiConfig); err != nil {

version.txt

@@ -1 +1 @@
-1.3.0
+1.9.0