Add Text: Prefix, Suffix & Insert Text in Filenames
Batchio's Add Text rule lets you prepend, append, or insert any string into your filenames at a precise position. Whether you need a project code before every name, a date stamp after it, or a tag injected at character five, the result appears instantly in the live preview before you commit.
How do you add a prefix to multiple filenames at once?
Adding a prefix is one of the most common batch renaming tasks. Photographers prepend shoot dates, developers add project codes, and archivists insert classification tags. With Batchio, you select your files, choose the Prefix position, and type your text. The live preview updates on every keystroke, so you can watch each filename change in real time. There is no separate confirmation step or dialog to dismiss.
Prefixes are applied to the base filename only, leaving the file extension untouched. This means adding "2026_" as a prefix to report.pdf produces 2026_report.pdf, not 2026_report.pdf.pdf. Batchio handles the extension boundary automatically so you never corrupt a file type by accident.
How do you add a suffix before the file extension?
photo.jpg becomes photo_final.jpg rather than photo.jpg_final.Suffixes are perfect for appending version labels, status tags, or size indicators. Common examples include adding "_v2", "_final", or "_lowres" to batches of exported assets. Batchio automatically places the suffix before the last dot in the filename, preserving the extension. If a file has multiple dots, such as archive.tar.gz, the suffix is inserted before the final extension component.
You can pair the suffix with a Numbering Sequence rule to create names like photo_edited_001.jpg. Because rules in Batchio execute sequentially, the suffix is applied first and the number is appended afterward, giving you predictable, layered results visible in the live preview.
Can you insert text at a specific position in filenames?
Positional insertion is useful when filenames follow a fixed structure and you need to inject a segment at a known offset. For example, if every filename starts with a six character date code and you want to add an underscore after it, set the position to 6 and type "_". Batchio applies the insertion to every selected file, and the live preview confirms the placement before you rename.
Negative positions are also supported, counting backward from the end of the filename. This lets you insert text a fixed number of characters before the extension without calculating the total length of each name. Combined with Find & Replace for pattern based edits, positional insertion covers scenarios where neither a prefix nor a suffix is in the right spot.
What happens when you combine add text with other rules?
A typical multi rule workflow might start with a Find & Replace rule to clean up the base name, followed by an Add Text prefix to stamp a project code, and finished with a numbering suffix. Each rule sees the output of the previous one, and the live preview reflects the cumulative result after all rules run. Our guide to adding prefixes on Mac walks through common prefix workflows step by step.
Because each rule is independent, you can enable or disable individual steps without rebuilding the entire chain. This modular approach means you can experiment freely. Toggle the prefix off to see what the filenames look like without it, then toggle it back on when you are satisfied. The non destructive workflow ensures that nothing changes on disk until you explicitly click the rename button.
Add Prefixes, Suffixes, and More in Seconds
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Marcel Iseli is an indie app developer and the creator of Batchio. He builds native macOS utilities focused on productivity and file management, with a focus on lightweight, subscription-free tools.