Respecting Focus and Meeting Status in Your Mac scripts (aka Don’t Be a Jerk)

In four words Barbara Krueger distills the Golden Rule into an in-your-face admonishment: Don’t be a jerk. It makes for a great coffee mug but how does this relate to shell scripting for a Mac admin and engineer? Well, sometimes a script can only go so far and you need user consent and cooperation to get the job done. Not being a jerk about it can pay off!

A good way to get cooperation from your users is to build upon a foundation of trust and respect. While IT has a long list of to-dos for users: “Did you reboot? Did you run updates? Did you open a ticket? Did you really reboot?” the users might have one for us: “Respect our screens when we’re in the middle of a client meeting and respect when Focus mode is turned on.” And they are right. That’s also two things. “Give an inch and they take a mile” I tell ya!

So how can we in IT can be considerate of our users? First, don’t do anything Nick Burns from SNL does. Second, use the functions below (and in my GitHub) to check if a Zoom, Teams, Webex, or Goto meeting is happening or if Do Not Disturb/Focus mode is on. When non-user-initiated scripts (i.e. daily pop-ups/nags/alerts) run they can bail or wait if the user is busy. If it were real life (and it is!) we wouldn’t walk into a meeting and bug a user, in front of everyone, to run update. If we did, they’d be more likely to remember how rude we were rather than actually running the updates. So let’s get their attention when they will be most receptive to what we have to say.

Detecting Online Meetings Apps

First up is inMeeting_Zoom which simply checks for the CptHost process and returns success or fail. Notice how this simple behavior can be used with an if/then statement. The return code is evaluated by the if, a zero is success and a non-zero is a failure. && is a logical AND and || is a logical OR

#inMeeting_Zoom (20220227) Copyright (c) 2022 Joel Bruner (
#Licensed under the MIT License

function inMeeting_Zoom {
	#if this process exists, there is a meeting, return 0 (sucess), otherwise 1 (fail)
	pgrep "CptHost" &>/dev/null && return 0 || return 1

if inMeeting_Zoom; then
	echo "In Zoom meeting... don't be a jerk"
	echo "Not in Zoom meeting"

Next is another process checker for Webex: inMeetng_Webex. What is a bit more unique is the process appears in ps in parentheses as (WebexAppLauncher)however pgrep cannot find this process (because the actual name has been rewritten by the Meeting Center process). We instead use a combination of ps and grep. A neat trick with grep is to use a [] regex character class to surround a single character, this keeps grep from matching itself in the process list. That way you don’t need to have an extra grep -v grep to clean up the output.

#inMeeting_Webex (20220227) Copyright (c) 2022 Joel Bruner (
#Licensed under the MIT License

function inMeeting_Webex {
	#if this process exists, there is a meeting, return 0 (sucess), otherwise 1 (fail)
	ps auxww | grep -q "[(]WebexAppLauncher)" && return 0 || return 1

if inMeeting_Webex; then
	echo "In Zoom meeting... don't be a jerk"
	echo "Not Webex in meeting"

Goto Meeting is more straightforward, although it should be noted that regardless of quote type, single or double, the parentheses must be escaped with a backslash. Otherwise, it’s the same pattern, look for the process name which only appears during a meeting or during the meeting preview and return 0 or 1 for if to evaluate, find it here: inMeeting_Goto

#inMeeting_Goto (20220227) Copyright (c) 2022 Joel Bruner (
#Licensed under the MIT License

function inMeeting_Goto() {
	#if this process exists, there is a meeting, return 0 (sucess), otherwise 1 (fail)
	pgrep "GoTo Helper \(Plugin\)" &>/dev/null && return 0 || return 1

if inMeeting_Goto; then
	echo "In Goto meeting... don't be a jerk"
	echo "Not in Goto meeting"

Lastly, Teams is a bit more complex, rather than looking for the presence of a process, we instead look for a JSON file in the user’s /Library/Application Support/Microsoft/Teams folder which has the current call status for both the app and the web plugin (the other methods above are for the app only). We’ll use the ljt to extract the value from the JSON. In fact I wrote ljt after starting to write this blog last week and realizing that jpt (weighing in at 64k) was just overkill. As a bonus to doing that, I just realized that bash functions can contain functions! Long ago I ditched using () in shell function declarations and just used the function keyword. Empty parentheses seemed decorative rather than functional since it’s not like it’s a C function that needs parameter names and types. However the lack of parentheses () apparently, prevents a function from being declared inside a function! Below I just wanted to make sure ljt doesn’t get separated from inMeetings_Teams

#inMeeting_Teams (20220227) Copyright (c) 2022 Joel Bruner (
#Licensed under the MIT License

function inMeeting_Teams ()(

	function ljt () ( #v1.0.3
		[ -n "${-//[^x]/}" ] && set +x; read -r -d '' JSCode <<-'EOT'
		try {var query=decodeURIComponent(escape(arguments[0]));var file=decodeURIComponent(escape(arguments[1]));if (query[0]==='/'){ query = query.split('/').slice(1).map(function (f){return "["+JSON.stringify(f)+"]"}).join('')}if(/[^A-Za-z_$\d\.\[\]'"]/.test(query.split('').reverse().join('').replace(/(["'])(.*?)\1(?!\\)/g, ""))){throw new Error("Invalid path: "+ query)};if(query[0]==="$"){query=query.slice(1,query.length)};var data=JSON.parse(readFile(file));var result=eval("(data)"+query)}catch(e){printErr(e);quit()};if(result !==undefined){result!==null&&result.constructor===String?print(result): print(JSON.stringify(result,null,2))}else{printErr("Node not found.")}
		queryArg="${1}"; fileArg="${2}";jsc=$(find "/System/Library/Frameworks/JavaScriptCore.framework/Versions/Current/" -name 'jsc');[ -z "${jsc}" ] && jsc=$(which jsc);[ -f "${queryArg}" -a -z "${fileArg}" ] && fileArg="${queryArg}" && unset queryArg;if [ -f "${fileArg:=/dev/stdin}" ]; then { errOut=$( { { "${jsc}" -e "${JSCode}" -- "${queryArg}" "${fileArg}"; } 1>&3 ; } 2>&1); } 3>&1;else { errOut=$( { { "${jsc}" -e "${JSCode}" -- "${queryArg}" "/dev/stdin" <<< "$(cat)"; } 1>&3 ; } 2>&1); } 3>&1; fi;if [ -n "${errOut}" ]; then /bin/echo "$errOut" >&2; return 1; fi

	consoleUser=$(stat -f %Su /dev/console)
	consoleUserHomeFolder=$(dscl . -read /Users/"${consoleUser}" NFSHomeDirectory | awk -F ': ' '{print $2}')
	storageJSON_path="${consoleUserHomeFolder}/Library/Application Support/Microsoft/Teams/storage.json"
	#no file, no meeting
	[ ! -f "${storageJSON_path}" ] && return 1

	#get both states
	appState=$(ljt /appStates/states "${storageJSON_path}" | tr , $'\n' | tail -n 1)
	webappState=$(ljt /webAppStates/states "${storageJSON_path}"| tr , $'\n' | tail -n 1)
	#determine app state
	if [ "${appState}" = "InCall" ]	|| [ "${webAppState}" = "InCall" ]; then
		return 0
		return 1

if inMeeting_Teams; then
	echo "In Teams Meeting... don't be a jerk"
	echo "Not in Teams Meeting"

Detecting Focus (formerly Do Not Disturb)

Last but not least is determining Focus (formerly Do Not Disturb) with doNotDisturb. As you can see there’s been a few different ways this has been implemented over the years. In macOS 10.13-11 the state was stored inside of a plist. For macOS 12 Monterey they’ve switched from a plist to a JSON file. A simple grep though is all that’s needed to find the key name storeAssertionRecords. If it is off, that string is nowhere to be find, when it’s on it’s there. Simple (as in Keep it Simple Stoopid)

#doNotDisturb (grep) (20220227) Copyright (c) 2022 Joel Bruner (
#Licensed under the MIT License

#An example of detecting Do Not Disturb (macOS 10.13-12)

function doNotDisturb()(

	OS_major="$(sw_vers -productVersion | cut -d. -f1)"
	consoleUserID="$(stat -f %u /dev/console)"
	consoleUser="$(stat -f %Su /dev/console)"
	#get Do Not Disturb status
	if [ "${OS_major}" = "10" ]; then
		#returns c-cstyle boolean 0 (off) or 1 (on)
		dndStatus="$(launchctl asuser ${consoleUserID} sudo -u ${consoleUser} defaults -currentHost read doNotDisturb 2>/dev/null)"

		#eval c-style boolean and return shell style value
		[ "${dndStatus}" = "1" ] && return 0 || return 1
	#this only works for macOS 11 - macOS12 does not affect any of the settings in
	elif [ "${OS_major}" = "11" ]; then
		#returns "true" or [blank]
		dndStatus="$(/usr/libexec/PlistBuddy -c "print :userPref:enabled" /dev/stdin 2>/dev/null <<< "$(plutil -extract dnd_prefs xml1 -o - /dev/stdin <<< "$(launchctl asuser ${consoleUserID} sudo -u ${consoleUser} defaults export -)" | xmllint --xpath "string(//data)" - | base64 --decode | plutil -convert xml1 - -o -)")"

		#if we have ANYTHING it is ON (return 0) otherwise fail (return 1)
		[ -n "${dndStatus}" ] && return 0 || return 1
	elif [ "${OS_major}" -ge "12" ]; then
		consoleUserHomeFolder=$(dscl . -read /Users/"${consoleUser}" NFSHomeDirectory | awk -F ': ' '{print $2}')

		#if Assertions.json file does NOT exist, then DnD is OFF
		[ ! -f "${file_assertions}" ] && return 1

		#simply check for storeAssertionRecords existence, usually found at: /data/0/storeAssertionRecords (and only exists when ON)
		! grep -q "storeAssertionRecords" "${file_assertions}" 2>/dev/null && return 1 || return 0
if doNotDisturb; then
	echo "DnD/Focus is ON... don't be a jerk"
	echo "DnD/Focus is OFF"

Since Focus can remain on indefinitely an end user may never see your pop-up. If so, build a counter with a local plist to record and increment the number of attempts. After a threshold has been reached you can then break through to the user (I certainly do).

Detecting Apps in Presentation Mode

A newer addition to this page is some code to detect fullscreen presentation apps that I cannot take credit for. Adam Codega, one of the contributors to Installomator hipped me to a cool line of code that was added in PR 268. It leverages pmset to see what assertions have been made to the power management subsystem. It uses awk to look for the IOPMAssertionTypes named NoDisplaySleepAssertion and PreventUserIdleDisplaySleep with some additional logic to throw out false positives from coreaudiod. In testing I’ve found this able to detect the presentation modes of Keynote, Powerpoint and Google Slides in Slideshow mode in Chrome (but not Safari), your mileage may vary for other apps. Another caveat is that when a YouTube video is playing in a visible tab, it will assert a NoDisplaySleepAssertion, however these will be named “Video Wake Lock” whereas a Slideshow presentation mode will have its name assertions named “Blink Wake Lock”. So I am adding an additional check to throw our “Video Wake Locks”. This may be more of a can of worms than you’d like, if so, user education to set Focus mode may be the way to go. A functionalized version can be found here: inPresentationMode

#inPresentationMode (20220319) Copyright (c) 2022 Joel Bruner (
#with code from Installomator (PR 268) ( Copyright 2020 Armin Briegel
#Licensed under the MIT License

function inPresentationMode {
	#Apple Dev Docs:
	#ignore assertions without the process in parentheses, any coreaudiod procs, and "Video Wake Lock" is just Chrome playing a Youtube vid in the foreground
	assertingApps=$(/usr/bin/pmset -g assertions | /usr/bin/awk '/NoDisplaySleepAssertion | PreventUserIdleDisplaySleep/ && match($0,/\(.+\)/) && ! /coreaudiod/ && ! /Video\ Wake\ Lock/ {gsub(/^.*\(/,"",$0); gsub(/\).*$/,"",$0); print};')
	[ -n "${assertingApps}" ] && return 0 || return 1

if inPresentationMode; then
	echo "In presentation mode... don't be a jerk"
	echo "Not in presentation mode..."

All together now

Putting it all together here’s how you can test multiple functions in a single if statement, just chain them together with a bunch of || ORs

#Joel Bruner - demo of meeting/focus aware functions for your script

#pretend we've declared all the functions above and copy and pasted them in here
function doNotDisturb()(:)
function inMeeting_Teams()(:)
function inMeeting_Zoom(){:}
function inMeeting_Goto(){:}
function inMeeting_Webex(){:}
function inPresentationMode(){:}

#test each one with || OR conditionals
#the FIRST successful test will "short-circuit" and no more functions will be run
if doNotDisturb || inPresentationMode || inZoomMeeting || inMeeting_Goto || inMeeting_Webex || inMeeting_Teams; then
	echo "In a meeting, presentation, or Focus is On... don't be a jerk"
	#do something else, like wait 
	echo "Not in a meeting..."
	#alert the user or do whatever you needed to do that might impact them

Using these functions in your scripts can help respect your users’ online meeting times and Focus states. Also it doesn’t hurt to document it somewhere and toot your own horn in a user facing KB or wiki. If and when a user complains about that pop-up that destroyed their concentration and their world, you can show them the forethought and effort you’ve taken to be as considerate as possible regarding this perceived incursion. This usually has the effect of blowing their mind 🀯 that someone in IT is actually trying to be considerate!

P.S. I’m pretty stoked that Prism.js can really jazz up my normally dreary grey code blocks! πŸ˜πŸ€“ I found a good WordPress tutorial here

ljt, a little JSON tool for your shell script

ljt, the Little JSON Tool, is a concise and focused tool for quickly getting values from JSON and nothing else. It can be used standalone or embedded in your shell scripts. It requires only macOS 10.11+ or a *nix distro with jsc installed. It has no other dependencies.

You might have also seen my other project jpt, the JSON Power Tool. It too can be used standalone or embedded in a script however its features and size (64k) might be overkill in some case and I get it! I thought the same thing too after I looked at work of Mathew Warren, Paul Galow, and Richard Purves. Sometimes you don’t need to process JSON Text Sequences, use advanced JSONPath querying, modify JSON, or encode the output in a myriad of ways. Maybe all you need is something to retrieve a JSON value in your shell script.

Where jpt was an exercise in maximalism, ljt is one of essential minimalism – or at least as minimal as this CliftonStrengths Maximizer can go! πŸ€“ The minified version is mere 1.2k and offers a bit more security and functionality than a one-liner.

ljt features:
β€’ Query using JSON Pointer or JSONPath (canonical only, no filters, unions, etc)
β€’ Javascript code injection prevention for both JSON and the query
β€’ Multiple input methods: file redirection, file path, here doc, here string and Unix pipe
β€’ Output of JSON strings as regular text and JSON for all others
β€’ Maximum input size of 2GB and max output of 720MB (Note: functions that take JSON data as an environment variable or an argument are limited to a maximum of 1MB of data)
β€’ Zero and non-zero exit statuses for success and failure, respectively

Swing by the ljt Github page and check it out. There are two versions of the tool one is fully commented for studying and hacking (ljt), the other is a “minified” version without any comments meant for embedding into your shell scripts (ljt.min). The Releases page has a macOS pkg package to install and run ljt as a standalone utility.

Thanks for reading and happy scripting!

jpt 1.0 text encoding fun

Besides JSON, jpt (the JSON power tool) can also output strings and numbers in a variety of encodings that the sysadmin or programmer might find useful. Let’s look at the encoding options from the output of jpt -h

% jpt -h
-T textual output of all data (omits property names and indices)
	-e Print escaped characters literally: \b \f \n \r \t \v and \\ (escapes formats only)
	-i "<value>" indent spaces (0-10) or character string for each level of indent
	-n Print null values as the string 'null' (pre-encoding)

	-E "<value>" encoding options for -T output:

	  Encodes string characters below 0x20 and above 0x7E with pass-through for all else:
		x 	"\x" prefixed hexadecimal UTF-8 strings
		O 	"\nnn" style octal for UTF-8 strings
		0 	"\0nnn" style octal for UTF-8 strings
		u 	"\u" prefixed Unicode for UTF-16 strings
		U 	"\U "prefixed Unicode Code Point strings
		E 	"\u{...}" prefixed ES2016 Unicode Code Point strings
		W 	"%nn" Web encoded UTF-8 string using encodeURI (respects scheme and domain of URL)
		w 	"%nn" Web encoded UTF-8 string using encodeURIComponent (encodes all components URL)

		  -A encodes ALL characters
	  Encodes both strings and numbers with pass-through for all else:
		h 	"0x" prefixed lowercase hexadecimal, UTF-8 strings
		H 	"0x" prefixed uppercase hexadecimal, UTF-8 strings
		o 	"0o" prefixed octal, UTF-8 strings
		6 	"0b" prefixed binary, 16 bit _ spaced numbers and UTF-16 strings
		B 	"0b" prefixed binary, 8 bit _ spaced numbers and UTF-16 strings
		b 	"0b" prefixed binary, 8 bit _ spaced numbers and UTF-8 strings

		  -U whitespace is left untouched (not encoded)


While the above conversion modes will do both number and string types, these options will work only on strings (numbers and booleans pass-through). If you work with with shell scripts these techniques may be useful.

If you store shell scripts in a database that’s not using utf8mb4 table and column encodings then you won’t be able to include snazzy emojis to catch your user’s attention! In fact this WordPress install was so old (almost 15 years!) the default encoding was still latin1_swedish_ci, which an odd but surprisingly common default for many old blogs. Also if you store your scripts in Jamf (still in v10.35 as of this writing) it uses latin1 encoding and your 4 byte characters will get mangled. Below you can see in Jamf things look good while editing, fails once saved, and the eventual workaround is to use an coding like \x escaped hex (octal is an alternate)

Let’s use the red “octagonal sign” emoji, which is a stop sign to most everyone around the world, with the exception of Japan and Libya (thanks Google image search). Let’s look at some of the way πŸ›‘ can be encoded in a shell script

#reliable \x hex notation for bash and zsh
% jpt -STEx <<< "Alert πŸ›‘"
Alert \xf0\x9f\x9b\x91

#above string can be  in both bash and zsh
% echo $'Alert \xf0\x9f\x9b\x91'
Alert πŸ›‘

#also reliable, \nnn octal notation
% jpt -STEO <<< "Alert πŸ›‘"
Alert \360\237\233\221

#works in both bash and zsh
% echo $'Alert \360\237\233\221'
Alert πŸ›‘

#\0nnn octal notation
% jpt -STE0 <<< "Alert πŸ›‘"
Alert \0360\0237\0233\0221

#use with shell builtin echo -e and ALWAYS in double quotes
#zsh does NOT require -e but bash DOES, safest to use -e
% echo -e "Alert \0360\0237\0233\0221"
Alert πŸ›‘

#-EU code point for zsh only
% jpt -STEU <<< "Alert πŸ›‘"
Alert \U0001f6d1

#use in C-style quotes in zsh
% echo $'Alert \U0001f6d1'
Alert πŸ›‘

The -w/-W flags can encode characters for use in URLs

#web/percent encoded output in the case of non-URLs -W and -w are the same
% jpt -STEW <<< πŸ›‘  

#-W URL example (encodeURI)
jpt -STEW <<< http://site.local/page.php?wow=πŸ›‘

#-w will encode everything (encodeURIComponent)
% jpt -STEw <<< http://site.local/page.php?wow=πŸ›‘

And a couple other oddballs…

#text output -T (no quotes), -Eu for \u encoding
#not so useful for the shell scripter
#zsh CANNOT handle multi-byte \u character pairs
% jpt -S -T -Eu <<< "Alert πŸ›‘"
Alert \ud83d\uded1

#-EE for an Javascript ES2016 style code point
% jpt -STEE <<< "Alert πŸ›‘"
Alert \u{1f6d1}

You can also \u encode all characters above 0x7E in JSON with the -u flag

#JSON output (not using -T)
% jpt <<< '"Alert πŸ›‘"'
"Alert πŸ›‘"

#use -S to treat input as a string without requiring hard " quotes enclosing
% jpt -S <<< 'Alert πŸ›‘'
"Alert πŸ›‘"

#use -u for JSON output to encode any character above 0x7E
% jpt -Su <<< 'Alert πŸ›‘'
"Alert \ud83d\uded1"

#this will apply to all strings, key names and values
% jpt -u <<< '{"πŸ›‘":"stop", "message":"Alert πŸ›‘"}' 
  "\ud83d\uded1": "stop",
  "message": "Alert \ud83d\uded1"

Whew! I think I covered them all. If there are newlines, tabs and other invisibles you can choose to output them or leave them encoded when you are outputting to text with -T

#JSON in, JSON out
jpt <<< '"Hello\n\tWorld"'

#ANSI-C string in, -S to treat as string despite lack of " with JSON out
% jpt -S <<< $'Hello\n\tWorld' 

#JSON in, text out: -T alone prints whitespace characters
% jpt -T <<< '"Hello\n\tWorld"'

#use the -e option with -T to encode whitespace
% jpt -Te <<< '"Hello\n\tWorld"'


Let’s start simply with some numbers. First up is hex notation in the style of 0xhh and 0XHH. This encoding has been around since ES1, use the -Eh and -EH respectively to do so. All alternate output (i.e. not JSON) needs the -T option. In shell you can combine multiple options/flags together except only the last flag can have an argument, like -E does below.

#-EH uppercase hex
% jpt -TEH <<< [255,256,4095,4096] 

#-Eh lowecase hex
% jpt -TEh <<< [255,256,4095,4096]

Next up are ye olde octals. Use the -Eo option to convert numbers to ye olde octals except using the more modern 0o prefix introduced in ES6

-Eo ES6 octals
% jpt -TEo <<< [255,256,4095,4096]    

Binary notation debuted in the ES6 spec, it used a 0b prefix and allows for _ underscore separators

#-E6 16 bit wide binary
% jpt -TE6 <<< [255,256,4095,4096]

#-EB 16 bit minimum width with _ separator per 8
% jpt -TEB <<< [255,256,4095,4096]

#-Eb 8 bit minimum width with _ separator per 8
% jpt -TEb <<< [15,16,255,256,4095,4096]

If you need to encode strings or numbers for use in scripting or programming, then jpt might be a handy utility for you and your Mac and if your *nix has jsc then it should work also. Check the jpt Releases page for Mac installer package download.

jpt 1.0, the JSON power tool in 2022

I’m happy to announce that jpt, the JSON power tool, has been updated to 1.0 and is available on my GitHub Releases page! It’s been over a year since the last release and I’ve been of working on, learning, and pondering what a really useful JSON tool could be and then working like heck to make it a reality.

jpt is a command line utility for formatting, querying, and modifying JSON. It can run on any version of macOS and most any Unix/Linux with jsc (JavaScriptCore) installed, otherwise it’s dependency free! For systems administrators and MacAdmins who need first class JSON tooling in their own shell scripts it can be embedded as a shell function in either bash or zsh. jpt was built to stand the test of time, needing only jsc and a shell, it will work on the newest macOS all the way back to OS X 10.4 Tiger!

There’s a year’s worth of bug fixes, improvements, and new features, let’s take a look at some of them.

Notable Features and Improvement

β€’Β jpt can now input and output multi-JSON documents like JSON Text Sequences (RFC 7464) plus other non-standard formats like NDJSON and JSON Lines and concatenated JSON. See: jpt 1.0 can deal with multiple JSON texts

β€’ Truncated JSON can be de detected in concatenated/lines JSON and repaired by closing up open strings, arrays and objects. See: Helping truncated JSON data with jpt 1.0

β€’ jpt can now fully rehabilitate JSON5 back to standard JSON. As I learned last year, there’s more mutant JSON than I realized! See: jpt 1.0 and JSON5 rehab

β€’ jpt can query JSON using both JSON Pointer, IETF RFC 6901 and JSONPath, a nascent draft RFC with powerful recursive search and filtering features.

β€’ jpt can manipulate JSON using JSONPatch, JSON Merge Patch, and some new merge modes not found anywhere else. See: merging JSON objects with jpt 1.0

β€’ shell scripters and programmers may find it useful that jpt has extensive string and number encoding capabilities. From classic encodings like hex, octal, and binary to more recent ones like URL/”percent” encoding and Unicode code points. See: jpt 1.0 text encoding fun

β€’ Need help finding visualizing JSON in new ways? jpt can output the structure of JSON in ways not seen, like JSONPath Object Literals which are simply the JSONPath, an equal sign, and the JSON value (e.g. $.ok="got it"). This simple and powerful declarative syntax can help find the exact path to a particular value and can also be used to quickly prototype a JSON object. See: jpt: see JSON differently

Try it out

There’s a lot to explore in jpt 1.0, download it from my GitHub with a macOS installer package in the Releases page. Check out my other jpt blog entries here at brunerd. As the IETF JSONPath standard takes shape I’ll be updating jpt to accomodate that standard. Until then, I hope this tool helps you in your JSON work, play, or research!

Decoding macOS automatic login details

In my previous post, Automating automatic login, we looked at how to create the /etc/kcpassword file used for automatic login by using only shell script and built-in command line tools. Why shell only? In preparation for the great scripting runtime deprecation yet to come, I say! Now it’s time to do the reverse for auto login. Let’s get those details back out! Who would need to do such a thing? Imagine a scenario where you the hapless Mac admin have inherited a bunch of Zoom Room Mac minis with auto-login enabled yet no one has documented the passwords used for them! If they are enrolled in Jamf there’s no need to guess what annoying l33t sp3@k password was used, let’s leverage our XOR’ing skills and knowledge of how kcpassword works to send those details back to Jamf.

To get the password back out of /etc/kcpassword we XOR the password again with the same cipher used to obfuscate it originally however but instead of padding it in multiples of 12, we will stop when a character is the same as the current cipher character. FYI when you XOR a value with itself the result is 00 but that’s an unnecessary operation, we can just compare the characters. VoilΓ‘, that’s it.

Here’s the gist of the kcpasswordDecode routine:

Now for something a bit more useful to those with Jamf or other management tools: getAutoLogin. It reports the auto login username, if set, and the decodes the /etc/kcpassword file, if present. Note that until macOS 12 Monterey /etc/kcpassword was not removed when Automatic Login was turned off in System Preferences! Here’s what getAutoLogin looks in the Jamf policy logs:

Plaintext passwords in your logs are probably not the best, but hey, how else you gonna figure out your dang Zoom Room passwords? After retrieving the credentials and storing somewhere more secure, like a password manager, make sure to Flush the policy logs! Thanks for reading, I hope this comes in handy or at the very least was informative and mildly entertaining. πŸ€“

Gist: kcpasswordDecode
Github: getAutoLogin

Automating automatic login for macOS

I recently had some Zoom Room Macs that needed some automation love and I thought I’d share how you can enable Automatic Login via script, perhaps you have several dozen and use Jamf or some other Mac management tool? Interested? Read on! Currently what’s out there are either standalone encoders only or part of larger packaging workflow to create a new user. The standalone encoders lacked some niceties like logging or account password verification and the package method added the required dependency of packaging if any changes were required. Above all, every script required Python, perl or Ruby, which are all on Apple’s hit list for removal in an upcoming OS release. For now macOS Monterey still has all of these runtimes but there will come a day when macOS won’t and will you really want to add 3rd party scripting runtimes and weaken your security by increasing attack surface when you can weaken your security using just shell? 😜 So for some fun, I re-implemented the /etc/kcpassword encoder in shell so it requires only awk, sed, and xxd, all out of the box installs. I also added some bells and whistles too.

Some of the features are:

  • If the username is empty, it will fully disable Automatic Login. Since turning it off via the System Preferences GUI does not remove the /etc/kcpassword file if it has been enabled (!)
  • Ensures the specified user exists
  • Verifies the password is valid for the specified user
  • Can handle blank passwords
  • Works on OS X 10.5+ including macOS 12 Monterey

For the Jamf admin the script is and for standalone usage get, both take a username and password, in that order and then enable Automatic Login if it all checks out. The difference with the Jamf script is that the first parameter is ${3} versus ${1} for the standalone version.

Also here’s a well commented Gist as a little show and tell for what the shell only version of the kcpassword encoder looks like. Enjoy!

Update: I meant to expound on how it didn’t seem that padding kcpassword to a length multiple of 12 was necessary, since it had been working fine on the versions I was testing with but then I tested on Catalina (thinking of this thread) and was proven wrong by Catalina. I then padded with 0x00 with HexFiend in a successful test but was reminded that bash can’t handle that character in strings, instead I padded with 0x01, which worked on some macOS versions but not others. Finally, I settled on doing on what macOS does somewhat, whereas it pads with the next cipher character then seemingly random data, I pad with the cipher characters for the length of the padding. This works for Catalina and other of macOS versions. πŸ˜…

Big Hat Tip to Pico over at MacAdmins Slack for pointing out this issue in pycreateuserpkg where it’s made clear that passwords with a lengths of 12 or multiples thereof, need another 12 characters of padding (or in some newer OSes at least one cipher character terminating the kcpassword data, thanks! πŸ‘

macOS Compatibility Fun!

Compatibility Questions

If you work with Macs and Jamf then you know every year there’s a new per OS Extension Attribute (EA) or Smart Group (SG) recipe to determine if macOS will run on your fleets hardware. However I asked myself: What if a single Extension Attribute script could fill the need, requiring only a periodic updating of Model IDs and the addition of new macOSes?

Then I also asked: Could this same script be re-purposed to output both text and CSV, not just for the script’s running host but for a list of Model IDs? And the answer was a resounding yes on all fronts!

EA Answers

So, my fellow Jamf admin I present to you in its simplest form you just run the script and it will provide ultra-sparse EA output like: <result>10.14 10.15 11</result> this could then be used as a Smart Group criteria. Something like “macOS Catalina Compatible” would then match all Macs using LIKE 10.15 or “Big Sur Incompatible” would use NOT LIKE 11, of course care would be taken if you were also testing for 10.11 compatibility, however the versionsToCheck variable in the script can limit the default range to something useful and speeds things up the less version there are. I hope this helps Jamf admins who have vast unwieldy fleets where hardware can vary wildly across regions or departments,

CSV Answers

Now if you provide a couple arguments like so: ./ -c -v ALL ALL > ~/Desktop/macOSCompatibilityMatrix.csv you will get a pretty spiffy CSV that let’s you visualize which Mac models over the years have enjoyed the most and least macOS compatibility. This is my favorite mode, you can use it to assess the OS coverage of past Macs.

See macOSCompatibilityMatrix.csv for an example of the output. If you bring that CSV into Numbers or Excel you can surely liven it up with some Conditional Formatting! This is the barest of examples:

Can you spot the worst and best values?

Text Answers

If you don’t use the -c flag then it’ll just output in plain or text, like so: ./ -v ALL ALL

iMacPro1,1: 10.13 10.14 10.15 11
MacBook1,1: 10.4 10.5 10.6
MacBook2,1: 10.4 10.5 10.6 10.7
MacBook3,1: 10.5 10.6 10.7
MacBook4,1: 10.5 10.6 10.7
MacBook5,1: 10.5 10.6 10.7 10.8 10.9 10.10 10.11
MacBook6,1: 10.6 10.7 10.8 10.9 10.10 10.11 10.12 10.13
MacBook7,1: 10.6 10.7 10.8 10.9 10.10 10.11 10.12 10.13
MacBook8,1: 10.10 10.11 10.12 10.13 10.14 10.15 11
MacBook9,1: 10.11 10.12 10.13 10.14 10.15 11
MacBook10,1: 10.12 10.13 10.14 10.15 11
MacBookAir1,1: 10.5 10.6 10.7
MacBookAir2,1: 10.5 10.6 10.7 10.8 10.9 10.10 10.11

Wrapping Up

Now, it’s not totally perfect since some models shared Model IDs (2012 Retina and Non-Retina MacBook Pros for example) but for the most part the Intel Mac Model IDs were sane compared to the PPC hardware Model IDs: abrupt jumps, overlaps, and re-use across model familes. Blech! I’m glad Apple “got religion” for Model IDs (for the most part) when Intel CPUs came along. I did attempt to go back to 10.1-10.3 with PPC hardware but it was such a mess it wasn’t worth it. However testing Intel, Apple Silicon and VMs against macOS 10.4 – 11+ seems to have some real use and perhaps you think so too? Thanks for reading!

jpt + jamf uapi = backupJamf-scripts

Jamf UAPI: JSON Only

I am a creature of habit, no doubt, however sometimes you must get out of your comfort zone. The Jamf Universal API (UAPI) is one such case, it is JSON only and not XM. Those tried and true xpath snippets will no longer work with JSON, in fact what tool do you use with JSON? macOS really doesn’t have a good built-in JSON tool and if your scripts are client side do you really want to have jq as a dependency? Good thing I wrote a JSON parser you can embed in your scripts this summer! In fact, when I finished writing my JSON power tool jpt, I needed to find some practical examples to demonstrate its utility. Looking at the UAPI it’s clear some parts are still a work-in-progress, however the endpoint for scripts is actually really good. It gives you everything in one go almost like a database query. That should made backing up scripts a breeze!

backupJamf-scripts. boom.

If you’ve used the Classic API from Jamf, it is a 1:1 ratio of scripts to API calls: 2 scripts? 2 API calls via curl. 200 scripts? 200 API calls via curl. The new Universal API reduces that down to 1 call to get everything (plus one call to get the token), it’s super fast and I love it. Check out backupJamf-scripts.command in my newly minted jamfTools repo on GitHub for a working demostration of both the Jamf UAPI and jpt’s in-script JSON handling. I hope you like it!

jpt + jamf uapi = scripts downloading scripts

Jamf & FileVault 2: Tips & Tricks (and more)

Raiders of the Lost Feature Requests

So there’s this old feature request at Jamf Nation (stop me if you’ve heard this one…) it’s almost 6 years old: Add ability to report on FV2 Recovery Keys (and/or access them via API) In fact, maybe you came here from there, watch out don’t loop! Continue!

The pain point is this: Keys are sent back to Jamf Pro (JSS) but then can only be gotten at manually/interactively through the web interface, not via API nor another method. For cases of mass migration to another JSS it sure would be nice to move those keys over rather than decrypt/re-encrypt. Well, I’ve got a few insights regarding this that I’d like to share that may help. ‘Cuz hey it’s 2020 and we’ve learned that hoarding is just silly.

Firstly, it should be pointed out that neither ye olde “Recovery Key Redirection” payload nor it’s replacement “Recovery Key Escrow” are needed to get keys to the JSS. There is another method and it’s what is used by the built-in “Filevault Encryption” policy payload to get the keys back to your JSS. Jamf references this method in this old script at their GitHub. I revamped the core bits a couple years ago in a (nearly 7 year old) feature request: Manually Edit FileVault 2 Recovery Key

Telling the JSS Your Secrets

The takeaway from that is to realize we have a way to explicitly send keys to the JSS by placing 2 XML files in the /Library/Application Support/JAMF/run folder: file_vault_2_id.xml and file_vault_2_recovery_key.xml. Also note, Jamf has updated the process for the better in the last two years: a jamf recon (or two) is no longer required to send the key and validate it, instead JamfDaemon will send it immediately when both the files are detected. Which is nice, but it’s the subsequent recon validations where we have an opportunity to get grabby.

Cold Lamping, Hard Linking

So here’s the fun part: When recon occurs there’s lots of file traffic in /Library/Application Support/JAMF/tmp all sorts of transient scripts hit this folder. What we can do is make hard links to these files as they come in so when the link is removed in tmp another exists elsewhere and the file remains (just in our new location). does exactly that (and a little bit more) can be easily modified to narrow it’s focus to the FileVault 2 key only, deleting the rest. What you do with the key is up to you: Send it somewhere else for safe keeping or keep it on device temporarily for a migration to another Jamf console. A script on the new JSS could then put that key on-disk into file_vault_2_recovery_key.xml file which will then import and validate, no decrypt/recrypt necessary. Hope this helps.

Cuidado Β‘ Achtung ! Alert

Jamf admins take note: Do you have hard coded passwords in your extension attributes or scripts? If so, then all your scripts are belong to us. Now, go read Obfuscation vs. Encryption from Richard Purves. Read it? OK, now consider what happens if you were to add a routine to capture the output of ps aww along with a hard-linking loop like in If you are passing API credentials from policies via parameter, then ps can capture those parameters and even if you try and obscure them, if we’ve captured the script we can de-obfuscate them. This is a good reason to be really careful with what your API accounts can do. If you have an API account with Computer record Read rights that gets passed into a script via policy and you use LAPS, then captured API credentials could be used to harvest LAPS passwords via API. Keep this in mind and we’ll see if any meaningful changes will occur in recon and/or the script running process in the future (if you open a ticket you can reference PI-006270 regarding API credentials in the process list). In the meantime make API actions as short lived as possible and cross your fingers that only you, good and noble #MacAdmins read this blog. 🀞

jpt: jamf examples pt. 2

Over in the MacAdmins’ #bash channel I saw a I question regarding how to get the Sharing states of Bluetooth devices from system_profiler. The most succinct answer was to awk out the values:

system_profiler SPBluetoothDataType 2> /dev/null | awk '/State: / {print $2}'

If you are using this for a Jamf Extension Attribute, I suppose it’ll do if you never want to allow any of them to be Enabled, but what if Internet Sharing was OK but not File Sharing? How would you match your Smart Group to multiple lines of unlabeled values? How would you match the first two but not the last two… and what if there was another USB Bluetooth device, that would add extra rows. Hmmm…

The answer for me, outputting the service name and the state on the same line. Since there isn’t a consistent line count from State: going back the service name, using something like grep -B n to include n lines of preceding data isn’t going to work.

          Bluetooth File Transfer:
              Folder other devices can browse: ~/Public
              When receiving items: Accept all without warning
              State: Disabled
          Bluetooth File Exchange:
              Folder for accepted items: ~/Downloads
              When other items are accepted: Save to location
              When receiving items: Accept all without warning
              State: Disabled
          Bluetooth Internet Sharing:
              State: Disabled

So you know what I say the answer to that is? That’s right, jpt the JSON Power Tool! It can parse the -json output from system_profiler in a more structured way and it allows for the discovery of as many applicable Bluetooth devices might be on the system.

Here’s a sample run with Internet Sharing turned On as well as Bluetooth Sharing turned On

file_browsing: disabled
object_push: enabled
internet_sharing: enabled

File Browsing is set to “Never Allow” but File Receiving is in the affirmative (Accept and Open, Accept and Save, or Ask). The addition of labels gives us the ability to create a Smart Group to match specific services like “file_browing: enabled” or any other combination thereof (perhaps internet_sharing should always be enabled, who am I to say what your requirements are!).

About the jpt

The JSON Power Tool (jpt) is a parser/manipulator for JSON documents written in Javascript and shell and can run standalone or embedded in your scripts bash or zsh and all the way back to OS X 10.4 Tiger! Check it out at: