macOS Quarantine on Executable Files
When using BBEdit 12.6 or later on macOS 10.13 or later, you may find
that after editing an executable file (such as a shell script, or any
script with a #! line), you are unable to run the file using Terminal
or any other application.
This is happening because of security measures in macOS. When the OS
detects changes to an executable file on disk, it will under certain
circumstances add a com.apple.quarantine extended attribute to the
file. The quarantine attribute subsequently prevents execution of the
file.
To work around this, open BBEdit's Preferences window and select the Application prefs pane.
If the "Sandbox access" option says "not allowed", click the "Allow" button and follow the prompts as indicated to grant access to your Mac's boot drive.
Once you have done so, that should prevent the OS from applying any further quarantine flags to your files.
Additional details are available in our App Sandboxing technical note.
