User Manual & Technical Guide
PatternRename
Help & Documentation
Everything you need to batch rename files efficiently — from basic usage to advanced patterns, RegExp, and Smart Fill logic.
1
Getting Started
PatternRename is a powerful web-based batch file renamer that uses pattern detection and smart-fill logic to rename images and other files — entirely in your browser, with no installation required.
1
Click ▶ Load & Reset to select a folder. The app requests permission to read and write files in that directory. No files are uploaded to any server — everything stays on your device.
2
The app automatically lists all supported files (JPG, PNG, SVG, and more based on your extension filter) and displays their timestamps alongside each filename.
3
Use the customisable columns to define your renaming rules. Each column adds one component to the final filename. Use plain text, patterns, or RegExp in any cell.
4
Click ✎ Rename All Files to apply changes. The Preview column shows exactly what each file will be renamed to before you commit.
PatternRename runs entirely in your browser. No files or filenames are ever sent to a server. Permissions are granted per-session via the browser's File System Access API.
2
Toolbar Reference
| Button | Function |
|---|---|
| ▶ Load & Reset | Selects a new folder and loads its files. If a folder was previously opened, it reopens without showing the picker. Hold Shift and click to force a new folder selection. |
| ✕ Change Folder | Clears the saved folder so the next Load click opens the folder picker again. Useful when switching to a different directory. |
| + Insert Row | Inserts a blank slot below the current selection. Note: this shifts the editable pattern values without affecting the underlying file list order. |
| ✕ Delete Row | Removes the currently selected row from the pattern table. |
| + Add Column | Adds a new naming component column. The final filename shown in the Preview column is the concatenation of all pattern columns in order. |
| ⚡ Smart Fill All | Analyses the pattern established in the first few filled rows and automatically fills the remaining rows. Requires at least two rows of input to detect a sequence. |
| Show All | Displays thumbnail previews for every image in the list, allowing visual confirmation before renaming. |
| ✎ Rename All Files | Applies all renames as shown in the Preview column. Duplicate filenames are rejected before any rename is performed. |
3
Advanced Naming Patterns
PatternRename supports much more than plain text. You can use special syntax in any column cell to extract, transform, or organise filenames dynamically.
A. Character Extraction (Positional)
Use square brackets to extract characters from the Original Filename (extension excluded). Positions are 1-based.
# Example filename: USA_PET_PUPPY_2026_A.jpg
[1-3] → USA # chars 1 through 3
[5,6,7] → PET # chars at positions 5, 6, 7
[5,2,8] → EPT # out-of-order extraction
[10-7] → YPPU # reverse: chars 10 down to 7
[5,6,7,3-1] → PETASU # combined: forward + reverse
[1-3] → USA # chars 1 through 3
[5,6,7] → PET # chars at positions 5, 6, 7
[5,2,8] → EPT # out-of-order extraction
[10-7] → YPPU # reverse: chars 10 down to 7
[5,6,7,3-1] → PETASU # combined: forward + reverse
Use
[1-50] in a RegExp-style column to grab the full original name (first 50 chars) — handy as a base for further transformations.
B. Regular Expressions (RegExp)
Extract dynamic parts of a filename using patterns wrapped in forward slashes /pattern/.
# Example filename: USA_PET_PUPPY_2026_A.jpg
/\d+/ → 2026 # first run of digits
/_[0-9]+/ → _2026 # underscore + digits
/DSC_(.*)/ → (capture group) # everything after DSC_
/[A-Z]{3}/ → USA # first 3 uppercase letters
/\d+/ → 2026 # first run of digits
/_[0-9]+/ → _2026 # underscore + digits
/DSC_(.*)/ → (capture group) # everything after DSC_
/[A-Z]{3}/ → USA # first 3 uppercase letters
Capture groups
( ) in a RegExp return only the captured portion, not the full match. This is useful for stripping prefixes or suffixes.
C. Folder Organisation
If any column value ends with /, PatternRename automatically creates that subfolder and moves the file into it.
# Column 1 = "Holiday/" Column 2 = "Photo"
Result: Holiday/Photo.jpg
# Nested folders also work:
# Column 1 = "2026/Summer/" Column 2 = "IMG_001"
Result: 2026/Summer/IMG_001.jpg
Result: Holiday/Photo.jpg
# Nested folders also work:
# Column 1 = "2026/Summer/" Column 2 = "IMG_001"
Result: 2026/Summer/IMG_001.jpg
Combine a positional extraction column (e.g.
[1-3] → USA) with a trailing / to automatically sort files into country folders: USA/, UK_/, etc.
4
Smart Fill Logic
The Smart Fill feature detects the pattern from the first rows you fill in and automatically completes the rest. You must provide at least two rows to establish a sequence.
| Pattern Type | Row 1, Row 2 Input | Resulting Sequence |
|---|---|---|
| Alphanumeric | Part_01, Part_02 | Part_03, Part_04 … |
| Arithmetic | 10, 20 | 30, 40, 50 … |
| Alphabetic | A, B | C, D, E … Z, A … |
| Repeating Blocks | A, A, B, B | C, C, D, D … |
| Fixed-suffix Alternating | DOF, DOK | DOF, DOK, DOF, DOK … |
| Leading-zero Numeric | A3B05, A3B07 | A3B09, A3B11 … (zero preserved) |
For repeating block patterns (e.g. A, A, B, B), write the entire repeat block twice in consecutive rows so Smart Fill can correctly detect the skip interval.
5
Shortcuts & Tips
Enter
Move focus to the cell directly below — Excel-style navigation through the pattern table.
Shift Click
Select a range of cells. Click the first cell, then Shift+Click the last to highlight all cells in between.
Click + Drag
Click and drag across cells to select a range in one motion.
Ctrl C
Copy selected cells. Paste directly into Excel or other spreadsheets — the data is tab/newline delimited.
Ctrl V
Paste data from Excel or another spreadsheet directly into the table.
Delete
While multiple cells are selected, clears all of them at once.
Shift + Load & Reset
Hold Shift while clicking Load & Reset to force the folder picker to open, even if a folder is already saved.
The Preview column always shows the exact final filename before any rename is committed. Check it carefully — PatternRename will reject the operation if duplicate filenames are detected.