How to save a copy of a file on Mac
Note My puts four copy commands together in its File menu, and each one does a job of its own. Here is which one writes a copy, and which one quietly moves you onto it.
You are about to make an edit you are not sure about, or you want to fork a working file into a variant and keep the original intact. So you want a copy. The awkward part is not making one — it is knowing which command leaves you editing the original and which one quietly moves you onto the new file. That is the one thing worth being sure of before you start typing, and it takes a minute to learn for good.
In Note My the copy commands live in one block of the File menu, immediately after Save As. This guide sorts out what each one is for.
Which copy do you actually want
"Duplicate" means at least three different things depending on what you are about to do. Decide which before you reach for a menu.
| What you want | Command | Where |
|---|---|---|
| A second tab of the same document, to work in without touching the first | Duplicate Tab ⌃⌘D | File menu |
| A second file on disk, beside the original | Duplicate File… | File menu |
| A copy written out to a place you choose | Save a Copy As… ⌥⇧⌘S | File menu, and the toolbar Save As menu |
| Continue your work in a new file instead of this one | Save As… ⇧⌘S | File menu, toolbar |
| The same file under a different name — no copy at all | Rename File…, or Rename… | File menu, tab right-click |
| The text itself, on the clipboard | Copy to Clipboard | Tab right-click menu |
The whole block — Save a Copy As…, Rename File…, Duplicate Tab, Duplicate File…, Reload from Disk ⌘R, Reveal in Finder ⇧⌘R, Open Containing Folder, Open With Default App, Open With…, Copy Path ⌥⇧⌘C, Copy File Name, Copy Containing Folder Path and Move to Trash… — sits in the File menu after Save As. The tab's own right-click menu carries the same set plus Open in Terminal, Save and Open in Terminal, and Copy to Clipboard.
The command that moves you onto the new file
File ▸ Save As… (⇧⌘S) writes the active tab under a new name or in a new place, and the tab then follows the new file. That is the behaviour to hold on to. After Save As you are editing the new file; the old one stops receiving your keystrokes at the moment you saved, and stays on disk exactly as it was.
That is the right command when you are deliberately continuing your work somewhere else — renaming a draft, moving a scratch file into a project folder, spinning a config into a per-environment variant you now want to work on.
When you want to leave a copy behind and stay exactly where you are, reach one line further down for Save a Copy As… (⌥⇧⌘S), the copy command that sits directly beside it — in the File menu and again in the toolbar's Save As menu. It writes the copy to the place you pick and leaves your cursor in the file you were already working in. Save As is the one that takes the tab with it; Save a Copy As… is the one that lets you carry on undisturbed. If you ever want it confirmed, the toolbar's path label names the file you are typing into.
If you are ever unsure which file you ended up in, read the toolbar. The identity capsule at the left shows the app name and the file you are in, and the path is a link — click it and the Finder opens with that file selected.
The whole family is also reachable without the menu bar. The toolbar's Save As item is a pull-down whose tooltip reads "Save As… and related save actions."; the menu under the chevron carries Save, Save a Copy As…, Rename File…, Reload from Disk and Reveal in Finder.
The two ways to rename
Two commands rename, and they are genuinely different, which is worth knowing when you are trying to tell an original from its copy in the tab bar.
| Rename… (double-click the tab) | Rename File… | |
|---|---|---|
| Destination | The same folder | Any folder you choose, through a save panel |
| Effect | Renames the file where it is; on an unsaved tab it changes the label only, and nothing on disk changes | An intentional move and rename |
| Unsaved edits | Renamed regardless, no prompt | Asks: Save and Rename…, Rename Without Saving, or Cancel |
| Name clash | Replace… or Cancel | Replace…, Choose Another Name, or Cancel |
Both act on the one file you have. When you want two, write the copy first with Save a Copy As… or Duplicate File…, then rename — that order lets you give the copy its own name while the original is still open in front of you, which is the surest way to keep the pair apart later.
The extension the save panel fills in for you
When a save panel opens, the name comes pre-filled with an extension that matches the language the document is already in. Accept it and the copy opens next time exactly the way the original does — same colouring, same indentation behaviour. The suggestion comes from our advanced language identifier, so the default you are handed is one the app will recognise again. It all happens on your Mac; nothing is uploaded.
Two consequences. First, if you have set a document to Custom…, no extension is suggested and the name field is yours — type the one you want. Second, the suggestion is only ever a starting point: type over it and the copy is written under whatever name you give it. If a copy ever opens as plain text rather than in the language you were working in, you can name the language yourself in a couple of moves: click the Identify pill in the status bar, choose the language from the override pop-up in the Language Inspector, and press Confirm. The choice sticks to that document, so the copy behaves exactly like the original from then on.
Making a scratch copy before a risky edit
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Save what you have first
Press ⌘S so the copy starts from a known state rather than from whatever was last written. Save writes the tab you are looking at and only that one — other tabs with unsaved changes keep them.
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Write the copy
Use File ▸ Save a Copy As… (⌥⇧⌘S) to write a copy where you choose, or File ▸ Duplicate File… to put a second file beside the first, in the same folder, in one step. Duplicate File… acts on the file on disk, so the ⌘S in the previous step is what readies it.
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Confirm where it landed
⇧⌘R reveals the current file in the Finder, and ⌥⇧⌘C puts its full path on the clipboard. If the tab you are in is not the one you expected, this is where you find out — before you start editing, rather than after.
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Edit, with the safety net running
From your first keystroke, our auto-recovery safety net is looking after the work you have not saved yet, so a risky edit does not depend on you remembering ⌘S. It runs on its own from the moment you start typing, always on and needing nothing from you, and a tab holding unsaved work wears a leading
*on its title so you can see at a glance what is still only in the editor. If the app quits unexpectedly, your tabs and the text you had not written out are waiting the next time you open it. -
Compare the two when you are done
With exactly two tabs open, Quick Compare pairs them immediately; with more, it asks you to click the partner tab. Our comparison view marks every difference in place and keeps the marks current while you type, so you can fix something and watch the difference disappear. Hold Shift while scrolling to move both sides together, and press Esc to leave compare mode. It is the quickest way to see precisely what the risky edit changed, line by line, before you decide which of the two files to keep.
Copying the contents rather than the file
Sometimes the copy you want is not a file at all — you want the text somewhere else. The tab's right-click menu offers Copy to Clipboard. From the Finder, right-clicking a single file gives Note My ▸ Copy Contents, alongside Copy as Markdown Code Block and Copy for AI (path + fenced) for when the destination is a message, a ticket or an AI chat. The Finder's folder menu also has New File from Clipboard, which is the shortest route from copied text to a real file; the same menu opens the folder and copies its path.
Pasting back is always plain text. Text lifted out of a web page or a word processor arrives as characters, never as fonts, sizes or colours you then have to strip out.
One save opens the whole File menu
Open a new document and the disk-side commands wait quietly until the tab has a file behind it. Press ⌘S once, choose a place, and the whole block lights up together: Duplicate File…, Save a Copy As…, Rename File…, Reload from Disk, Reveal in Finder, Copy Path and the rest are all live from that moment on. It is a single keystroke between a scratch tab and the full set of copy commands.
An untitled tab is looked after in the meantime. Our auto-recovery safety net covers a tab you have never saved just as it covers one with a file behind it, so notes typed straight into a fresh tab survive the app closing. You can open a tab, think out loud in it for an hour and give it a home on disk whenever you are ready.
There is a related case worth knowing. If the file underneath a tab goes missing, the tab stays open with your text intact and its title becomes Foo (missing). Your next ⌘S opens a save panel and asks where to put it, so the work is never stranded.
Troubleshooting
I used Save As and now I am editing the copy
Nothing is lost — both files are on disk, and the original holds everything up to the moment you saved. Reopen it with ⌘O, or from the Finder. To check which file a tab is pointing at, read the path label in the toolbar's identity capsule, or hover it for the full path.
The save panel suggested an extension I did not want
Type your own over it; the suggestion is a starting point, not a rule. If the copy then opens as plain text rather than in the language you were working in, click Identify in the status bar and set the language yourself — our advanced language identifier stands behind the suggested extension, and the override lets you name the language you want on any document. Renaming the copy with the usual extension has the same effect.
Saving fails with a permission error
The app is sandboxed and has read-write access only to files and folders you have chosen yourself, so writing a copy into a folder you have never pointed it at can be refused by macOS rather than by the app. The route back is the one the message itself names: use File ▸ Save As…, pick the destination folder in the save panel, and save the copy there. Choosing it there is what grants the access.
The copy and the original look identical in the tab bar
Double-click a tab title to rename inline — a real rename, in the same folder — or widen the tabs by dragging a tab's right edge. The tidier fix is upstream: give the copy a distinct name at the moment you write it.
Something changed the file while I had the copy open
You are told. When a file changes underneath you, a sheet offers Reload or Keep My Version. Choosing Keep My Version means the text in front of you is the version that counts; the tab is marked unsaved, and our auto-recovery safety net holds on to it until you write it out. The orange dot on a tab means "changed on disk" — it is not the unsaved marker, which is the leading *.
What else a copy is good for
Once two files exist, the rest of the File menu is built around having both of them in play.
- Keep checkpoints you chose yourself. Save a Copy As… before each risky stretch and give every copy a name you will recognise a week later — a date, a step number, a word for what you were about to try. Because you stay in the original, you can lay down a checkpoint mid-thought and carry straight on typing. Checkpoints you named yourself beat any list you have to decipher afterwards, and they sit in a folder you picked, on your Mac, where you can see them.
- Put the two side by side. Open the copy in a second tab and Multi View gives each tab its own pane, so the original and its variant sit next to each other on one screen. Read across, lift a paragraph from one into the other, and keep both in view while you decide.
- Watch the differences shrink as you work. Quick Compare pairs the two files, and our comparison view keeps its marks current while you type — so a difference disappears the moment you reconcile it, and an empty screen tells you the pair has converged.
- Let the copy go its own way. A variant is yours to take somewhere the original was never going: a per-environment config, a rewritten draft, a stripped-down version to send on. When you want to know how far apart the two have travelled, compare them and read it off.
- Take the copy elsewhere. Reveal in Finder puts it in front of you, Open Containing Folder gets you to its neighbours, Copy Path and Copy File Name hand it to a terminal or a message, and Save and Open in Terminal writes the tab out and drops you at a prompt in the right place. Open With Default App and Open With… pass the copy to whatever else you want to look at it in.
- Start from the Finder. The Finder extension's file verbs act on the files you have selected, so you can go from a folder full of copies straight into tabs, without finding your way back through an open panel first.
All of it happens on your Mac. Copies you write, the paths you copy and the comparisons you run stay between you and your disk.
Frequently asked questions
What is the difference between Save As and Save a Copy As?
Save As (⇧⌘S) writes the tab under a new name or place and the tab then follows the new file — you carry on in the copy. Save a Copy As… (⌥⇧⌘S) writes the copy to the place you pick and leaves the tab bound to the file you were already in, so you carry on in the original. That is the whole difference between them, and the toolbar's path label names the file you are typing into whenever you want it confirmed.
Does duplicating a tab create a file in the Finder?
Duplicate Tab (⌃⌘D) is an editor command; Duplicate File… is the one that acts on disk. In general, nothing lands in the Finder until you save it yourself — though our auto-recovery safety net is looking after the unsaved work either way.
Do I need to save a new document before I duplicate it?
Save it once with ⌘S and the disk-side commands — Duplicate File… among them — are live from that moment on. You can also go straight for Duplicate File… on a fresh tab: a sheet offers Save and Duplicate…, which threads the two together and hands you the save panel and then the duplicate panel in one run. Until the tab has a file behind it, it lives purely in the editor, with our auto-recovery safety net holding on to what you have typed.
How do I copy a whole file's text without opening it?
Right-click it in the Finder and use Note My ▸ Copy Contents. The same menu offers Copy as Markdown Code Block and Copy for AI (path + fenced) when the text is going into a document or a chat.
Will the copy open in the same language as the original?
If you accept the suggested extension, yes. Our advanced language identifier stands behind that suggestion, so you get the same colouring and the same editing behaviour in both files. If you type a different extension, the copy may open as plain text — set it right from the Identify pill in the status bar.
Is any of this sent anywhere?
Every copy you make stays on your Mac. Nothing is uploaded and nothing is sent anywhere: no telemetry, no account, no update check. The app is fully sandboxed, with read-write access only to the files you choose yourself, so your work goes where you put it and nowhere else.