MacOS – Running shell scripts in single-user mode

bashmacosscriptsingle-user

I'm planning on running a couple of scripts in single-user mode to speed up (and simplify for less savvy users than myself) the configuring of a few aspects of some Macs that I set up for other people.

I've read the few threads I could find about this, and my question is simply is there anything I should be particularly aware of when it comes to running scripts from single-user mode?

I'm aware that I can't invoke any commands/apps that would require a GUI to load, and that the /sbin/fsck and /sbin/mount commands would still be required before a script can be run at all.

Two more specific questions: If I set the script as executable before depositing it on the disk image that will be booted in single-user mode, will it remain executable?

And lastly, when it comes to removing user accounts I've seen on some threads e.g this one the need to invoke this command:

launchctl load /System/Library/LaunchDaemons/com.apple.opendirectoryd.plist

However, as I simply want to rm various files – is there any need to do this, the process seems to work just fine without it?

Best Answer

Yes, files flagged as executable will still be executable under Single User Mode.

opendirectoryd is just for handling logins/authentication and using root doesn't require that, and you don't need to launch it if you just intend to manage files.

Related Solutions

MacOS – How to remove a user via single user mode in 10.7

There are several problems with the script you posted.

Don't remove /Users/Shared - iTunes needs it and will fail on certain store and sharing operations.

dscl on Lion will still whine if you start it (it's looking for the missing plist) - even if you launch /System/Library/LaunchDaemons/com.apple.opendirectoryd.plist as Ingmar Hupp has suggested.

I've never been one to worry about cleaning up the groups since I'm deleting user 501. The system will just add UID 501 back into the Admin and Staff groups the next time the Setup Assistant boots, so I do the following: (assume the short name of the user 501 is test)

⌘+S
/sbin/mount -uw /
cd /var/db/dslocal/nodes/Default/users/
rm test.plist
rm -rf /Users/test
rm /var/db/.AppleSetupDone
halt

I do use the official Users & Groups Preference Pane to delete all users except 501 and/or create the test user as 501 as needed since launchd can have jobs stuck if the users you are clearing aren't trivial users set up for simple updates as your case allows.

I would avoid saving a WiFi password or setting up WiFi outside the user account or use ethernet for your updates if you want to be fastidious about leaving as little of your settings behind (especially if the SSID/name isn't generic like Apple Network or has WEP/WPA keys).

MacOS – How to run AppleScript (.scpt) as LaucnDaemon by root

Assuming your launchd job is correctly set-up, you may be reaching a limitation of AppleScript.

AppleScript Requires a GUI (Aqua Session)

If your AppleScript is launched using launchd as a user root process, it will not have a graphical user interface associated. The majority of AppleScript requires a graphic user interface to work consistently. Depending on the version of OS X, it may work, but it is not designed to.

Processes on OS X can not trivially cross between user sessions.

Do Shell Script

A more robust approach is to separate out the functionality needing higher privileges into a shell script such as bash, perl, ruby, or python.

Your AppleScript can then call that script using AppleScript's do shell script:

do shell script "command" user name "me" password "mypassword" with administrator privileges

If you need to avoid embedding a username and password, this is possible but beyond the scope of this question.

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