Change File Permissions or Lock a File on a Mac Without Terminal

Want a script to run when you double-click it, a folder that others can read but not change, or a signed contract that nothing can overwrite by accident? On a Mac, that is a matter of permissions and of the Locked flag, and you can change both without typing a command.

The short answer:

• In the Finder: select the item and choose File › Get Info (⌘I). Tick Locked in the General section to lock it. At the bottom, Sharing & Permissions gives you, your group and everyone Read & Write, Read only or No Access. There is no setting for the execute permission.
• In Folia Files: select the item and press ⌘I (File › Info). The Permissions section has a Read, Write and Exec. checkbox for Owner, Group and Everyone, shows the number you would type after chmod, and has a Locked checkbox. Each click applies at once, and ⌘Z undoes it.

Permissions and Locked are two different things

Every file and folder on your Mac has an owner (usually you) and a group (staff for the files in your home folder). Each of them, and everyone else, gets three permissions:

• Read: open the file, or see what a folder contains.
• Write: change the file, or add, rename and delete items in a folder.
• Execute: run the file as a program or a script, or, for a folder, go into it at all.

Terminal writes them as letters, rw-r--r--, or as a number: 4 for read, 2 for write and 1 for execute, added up for the owner, the group and everyone, in that order. 644 (rw-r--r--) is a typical document: you read and write, the others only read. 755 (rwxr-xr-x) is a typical folder or script.

Locked is not a permission. It is a flag on the item itself (uchg, in Terminal's words). While it is set, the item can't be changed, renamed or deleted, by you included, whatever its permissions say. It is the right tool for a file that must stay as it is: a signed contract, a template, an archived invoice.

In the Finder: Get Info

Lock a file

1. Select the file and choose File › Get Info (⌘I).
2. In the General section, tick Locked.

Untick it to unlock the file. Apps can still open a locked file, but they can't save changes to it, and the Finder asks before putting a locked item in the Trash.

Change who can read and write

1. In the same window, open Sharing & Permissions at the bottom.
2. If the padlock at the bottom right is closed, click it and enter an administrator's name and password.
3. Next to each name, choose a privilege: Read & Write, Read only or No Access. A folder also offers Write only (Drop Box): others can put files in it without seeing what it holds.
4. For a folder, the action menu at the bottom of the window has Apply to enclosed items…, which gives the same privileges to everything inside. Use it with care: it changes every item at once, and there is no undo.

A 644 document shows three lines: you with Read & Write, staff and everyone with Read only.

What the Finder leaves out

• The execute permission. No privilege turns it on or off. That is the classic dead end: double-click a downloaded .command script and macOS says you don't have the appropriate access privileges, then points you to Get Info, which has no box for it.
• The number. Get Info never shows 644 or 755, which is what a tutorial, a web host or a README asks you for.

The same in Terminal, for the record

chmod u+x backup.command makes a script executable for you, chmod 644 notes.txt sets the numbers, chflags uchg contract.pdf locks a file and chflags nouchg contract.pdf unlocks it; ls -l shows the letters. To start Terminal in the right folder, see how to open Terminal in the current folder.

In Folia Files: the Permissions section of Info

Folia Files puts all of it in one place, in the Info of the selected item, with the execute permission, the number and the lock side by side.

Where to find it

• File › Info (⌘I), or Info in the right-click menu, opens an Info window for the item, with every section. Select up to ten items and each one gets its own window.
• File › Show Info Module (⌃⌘I) shows the Info module, which follows whatever you select. Like the other modules, it can sit in the right sidebar, under the left sidebar's list or in a pane of its own. Permissions is shown unless you turn it off under Shown Fields in the module's gear menu.

The same Info holds the item's tags and its Finder comment (more in how to add a note to a file or folder).

Read, Write, Exec.

The Permissions section is a small grid: Read, Write and Exec. across, Owner, Group and Everyone down, with the owner's and the group's names under their labels. Below it, the number and the letters (644 rw-r--r--) follow every click, so you can match exactly what you were asked for.

Each checkbox applies as soon as you click it. There is no padlock to open and no Apply button.

Make a script executable

1. Select the script and press ⌘I.
2. In Permissions, tick Exec. on the Owner row. The number goes from 644 to 744.
3. If other people who use this Mac must run it too, tick Exec. for Group and Everyone as well: 755.

Lock a file

Tick Locked under the grid, and untick it to unlock. It is the same flag as the Finder's checkbox, so the Finder shows the file as locked too, and the other way round. A locked item also refuses permission changes: unlock it, change its permissions, then lock it again.

Undo a change

Clicked the wrong box? Press ⌘Z (Edit › Undo) in the same window and the previous permissions, or the previous lock state, come back. ⇧⌘Z redoes it, and each click is a step of its own. These changes are not listed in the Operations history, so ⌘Z is the way back: in an Info window, before you close it.

Folders

On a folder, Exec. is what lets you go into it. That is why folders usually show 755: Read alone is not enough to open them.

If you untick Exec. for Owner on one of your own folders, you can no longer open it, but you can still select it in its parent folder and tick the box again.

What Folia Files doesn't change

• Items that belong to someone else. macOS lets only an item's owner change its permissions (or an administrator, with a password), and Folia Files never asks for that password. Click a box on a file owned by root and it springs back, with an orange line under the grid: "Change denied: you aren't the owner (root)." For those, the website edition has File › Finder Info Window (⌥⌘I), which opens the Finder's Get Info window for the same item, padlock included.
• Several items at once. The Permissions section only appears when one item is shown, and there is nothing like Apply to enclosed items….
• The owner and the group. Their names are shown, not changed, and the extra users or groups the Finder can add to its Sharing & Permissions list don't appear in the grid.
• Read-only disks. Nothing can be changed there: the box springs back.

What to leave alone

Change permissions on your own documents, scripts and project folders, not on what macOS and your apps rely on. Leave the System and Library folders, the apps in Applications and your own Library folder (~/Library) as they are: a wrong permission there can stop an app from opening or from saving its settings. And never take your own Read, Write or Exec. away from your home folder or from its Desktop, Documents and Downloads folders.