ljt – brunerd

Exploring Unicode in macOS with clui

July 20, 2023July 30, 2023 brunerd 1 Comment

My new tool clui, pronounced “clue-ee” offers Command Line Unicode Info with the ability to export to a variety of formats like CSV, JSON, YAML, RTF and more. While I’ve written a few macOS command line tools geared to the Mac Admin like jpt the JSON power tool, ljt the little JSON tool, shui for easily adding AppleScript dialogs to your shell script, and most recently shef a Unicode text encoder and formatter for shell scripters. This is one is almost “just for fun” although you might find some practical uses for it. Writing shef opened my eyes to the stunning amount of detail and craftsmanship in macOS’ Unicode-aware fonts, which comprise not just the alphabets of the world but signs, symbols, and even Egyptian hieroglyphics! While macOS’s built-in Character Viewer does a pretty good job to group and display these characters it’s a painstakingly manual process if you want to get info on a range of characters. I hope clui makes it fun and easy to poke around the vast Unicode neighborhood.

If you don’t feel like reading you can watch this.

Starting with Character Viewer

First let’s take a look at Character View, perhaps you don’t know some of it’s features. If you quickly press the dedicated “globe” 🌐 button on newer Macs (or the keyboard combo Control-Command-Spacebar on older models) it will likely open up Character Viewer in it’s default mini-sized version with preset categories along the bottom. You can click on a symbol or character and it will insert the text in your current app. The real fun begins when you click the little icon in the upper right to expand the view.

The window will expand to show more information: The code point(s) in hexadecimal (U+hhhh), the UTF-8 encoding bytes, and related characters. You will need to double-click these to insert them into your current app.

You can also Customize the List of categories that appear in the left column by clicking the encircled ellipsis…

The one that has everything in it is Unicode under the Code Tables group at the bottom of the list.

You can right-click or control-click on a character to Copy Character Info into the clipboard. In the example below, we discover that what most Mac folks would call ⌘ “Command” is also known as the “Place of Interest Sign”. Whaddya know!

This is all well and good but who’d want to do that for thousands of characters?! What if someone wanted this info at the command line? It got me thinking: There’s Got to Be a Better Way!™

Searching for the Source

The first order of business was looking for where macOS kept it’s naming information and if it was possible to extract that information with command line tools. It ended up being in two files, a SQLite database and a plist. Here’s their full paths:

#Single code point characters and Unicode symbols
/System/Library/Input Methods/CharacterPalette.app/Contents/Resources/CharacterDB.sqlite3
#plist of single and multiple code point Emoji
/System/Library/PrivateFrameworks/CoreEmoji.framework/Versions/A/Resources/en.lproj/AppleName.strings

There is some overlap with CharacterDB.sqlite3 and AppleName.strings where Apple choose to use different phrasing for an Emoji vs. Unicodes name, but in general the former has single code point entries, while the latter has both single and the multi-codepoint Emoji sequences. clui will report on both, putting a semi-colon in between each version, you can also output discretely with the -D option. Descriptions/info fields are converted from uppercase to lowercase BECAUSE WHO LIKES GETTING YELLED AT?! 🙉 Although you can preserve case with -p which can help with deciphering the internal (and unlabeled!) columns Apple uses in the descriptions of the CJK Ideographic ranges.

clui in Action: Practical Examples

Simple Lookups

If you’d like to see what all the options and modes run clui -u to get the “usage” output, or take a look at on clui’s GitHub page. To start with, clui is built to ingest both “regular” characters and also representation of Unicode code points in hexadecimal in the style of: U+hhhhh or 0xhhhhh. Ranges can also be specified by simply adding a hyphen between to characters or codepoints and it can both ascend and descend. The default output is CSV.

Apple doesn’t want to call anyone a nerd apparently, but that’s OK I embrace it.

For multiple code point emoji you can enclose the code point representations in quotes. Spaces within quotes are only used delimit each code point and are not part of the composite character.

The -X expansion option will display the all the code points together, then break out each component

-x will expand the input and break out each code point without showing the composite character

Working with Categories and Groups

clui can tap into categories and groups by leveraging the the plists inside the Resources folder of CharacterPallette.app. These plists contain a mix of 0x code point representations and literal characters. The list option -L takes the upper and lowercase arguments of c or g for exactly what you think, categories and groups! -Lc gets categories marking those with internal subsections with an asterisk * and -LC will expand those categories to include the subsections within. All list outputs are CSV and includes a header row, -h will suppress headers. In this excerpted example below you can see Arrows contains a number of subsections:

clui acts on a categories when you use the -C option and input one or more categories. If no subsection is specified the complete category will be output. Some can be quite large and take several minutes to output! If you are outputting RTF or JSON and redirecting to a file, if you interrupt with Control-C the output will be properly closed up, so it will still be valid.

As you can see at the bottom of the list, not all characters have renderings. However, if you double click those question mark glyphs ⍰ to select and copy them (CSV is nice that way), you will get that exact character. I used the apl “quad question” character (U+2370) above to get something close to it for this example, but don’t let the generic visual representation fool you, it is unique. You can use Character Viewer to see if any other fonts have alternate graphical representations, since Terminal is using only the currently selected font to display output. Update: It will fall back to a font that has a representation if needed. I recommend the free GNU Unifont for “Glyphs above the Unicode Basic Multilingual Plane”, which fills in some of the gaps of Apple fonts (like the LCD-like segmented numbers U+1FBF0-U+1FBF9)

Groups are about the same thing as categories except groups are comprised of multiple categories. -Lg lists all groups and -LG will expand the constituent categories within.

You can use -G like -C specifying one or more groups. If you include a category name (comma delimited) after the group, it’ll simply report that category as if you’d used it solely with -C. Here’s an example of the first group AdditionalModernScripts and the member category CanadianAboriginalSyllabics . For variety I’ve added -h to hide the header row from the CSV output.

CSV Looks Great in QuickLook

Just in case you didn’t know, Quicklook will display files with a csv extension really nicely. Here’s the CanadianAboriginalSyllabics above as seen in Quicklook, you can even select characters from within Quicklook, pretty nice!

CSV Can Look Even Better in Numbers

If you want to work with CSV in Numbers it will do quite nicely. Here’s a little tip for better legibility:

Select column A from the top of the column
Command ⌘ click on A1 to deselect it
Format the text to a larger size (like 50 points or higher)
Adjust the column width a bit wider
Save it as a .numbers file to retain formatting

Some of these Emoji will make you hungry

Pro Tip: Quicklook will not let you select any text from a Numbers document! However if you click and drag anywhere in the Quicklook contents to the Desktop (or into Preview), it will export a seamless PDF with no page breaks! Then you can select text from the PDF in QuickLook. Who knew?! Now back to clui features!

Get a Good Look at Those Emojis in Rich Text Format!

A late entry feature to clui is RTF (Rich Text Format) output. This enables clui to present the characters in larger sizes without requiring additional work from you (as seen above in Numbers)! The format is the same as the “plain” output (-Op) which does not label the fields, simply use the -Or option

Your best bet with RTF output is to either redirect it to a file like this: clui -Or -C Emoji > Emoji.rtf or pipe it into pbcopy like so: clui -Or -C Emoji | pbcopy. There’s a neat feature in pbcopy that detects the RTF header data and allows you to paste into TextEdit as rich text. You can also specify the font sizes withthis option: -f <char size, info size>

Searching by Description

clui can also search descriptions for multiple words and phrases. In this example I’ll search for magic, castle, and “clock face” using the -Sd (search descriptions) option. If I had searched just for clock I’d have also gotten hits for “clockwise arrows” since it search for substrings.

Searching by Character

Now, if you search for the usage of a single alphabetical character you’ll probably get one hit but macOS also has a database of “related characters” which are similar look-alike letters. You know, like the Subject lines of spam: “𝔅𝗢𝔾𝕆 𝐒𝖆𝓵𝙚 ‼”. Let’s use -SC to search for "a" plus related characters. I’ve trimmed the output to get some of the more interesting characters in this screenshot

When you start searching for symbols you’ll start discovering Emojis constructed using existing symbols and zero-width joiners (ZWJ, U+200D), these are called ZWJ Sequences (and ZWJ is apparently pronounced “zwidge”) . Let’s use -Sc to search for anything with the female sign ♀.

Let’s examine “woman surfer” (BTW: 100 Foot Wave Season 2 is awesome!) with the -X option to expand all component code points with the complete glyph as-is at the top:

The first line has the Emoji sequence as-is, then each individual component that comprises it: a gender neutral surfer (U+1F3CF), a ZWJ (U+200D), the female sign (U+2640), and variation selector 16 (U+FE0F). You may also notice one of the quirks of Terminal: Sometimes pasted input does not fully render as a unified Emoji!

Fitzpatrick Modifiers for Skin Color

To be honest I’d never heard of the Fitzpatrick scale before working on clui! It’s simply a scale of 6 types of skin color. The Unicode modifier combines Types 1 & 2 into U+1F3FB. Let’s demonstrate a search by description and then again with their ranges. Simply specify the range using standard Unicode notiation U+hhhhh with a hyphen in between.

If you search for an Emoji with a Fitzpatrick Modifier you won’t get a hit in the databases. As a convenience clui will detect this and remove the modifier to get the description. Using the -F will also display the sequence without the modifier. We can combine it with -X for expanded output with a a summary.

As you can see the sequence without the modifier is shown, then the original sequence with the Fitzpatrick modifier then each component part: surfer, Fitzpatrick modifier type-6, a ZWJ, female sign, and a variation selector.

On Variation Selectors

To be honest I’d never known about variation selectors before working on this, more info on Emoji Presentation Sequences can be found here. The two most common variation selectors are pretty easy to understand: U+FE0E is “variation selector 15” and it is used to explicitly specify the text/non-graphic version and U+FE0F, “variation selector 16” gives you the emoji/graphic version. Watch (U+231A) is a good example of this. It’s at the discretion of the OS on how to render a glyph. In this case U+231A is rendered in the emoji style of an Apple Watch⌚️by default. When combined with U+FE0E, it turns into ye olde Mac OS watch ⌚︎, this is the “text version”. Adding U+FE0F does nothing to change the appearance since it was already rendered in the emoji style without it.

If you’d like to search for every character with a variation selector that is tracked in macOS’s database, you can run this query: clui -Sc U+FE0E U+FE0F A definitive list can be found here.

Encoding Options

So far we’ve just seen the default uppercase hexadecimal (-Eh) UTF-8 encoding. In the vein of shef, clui can output in various styles of encoding: \x hex escapes (-Ex), octal \nnn (-Eo), leading zero octal \0nnn (-E0), UTF-16 Javascript encoding (-u) and zsh style UTF-32 \U code points (-EU).

Formatting output

Besides the beautiful RTF output and functional CSV output, clui can also output characters simply space delimited, without any other data (-Oc).

JSON (-Oj) and JSON Sequences (-OJ) can be had as well. The difference between JSON and JSON Sequence is that JSON will be an array of objects, whereas JSON Sequences are JSON objects delimited with U+1E the “record separator” as ASCII calls it or “information separator two” as Unicode knows it to be and newlines. Both jq and jpt can handle JSON sequneces.

Lastly we have YAML (-Oy) the superset cousin of JSON. My JSON string encoder jse gets some use in clui to encode strings and descriptions for these output modes.

Making it work for you (and me)

I spent a lot of time trying to make clui work in an intuitive way, it replicates the core features of Character Viewer with plenty of bonus functionality thrown in. It may not be something you use daily, but it might come in handy when you get an email from let’s say, tim@аррlе.com. You could run that string through clui in “expand” mode (-x) to analyze on each letter in the string. You might be surprised and perhaps disappointed that perhaps “Tim Apple” did not send you that email.

Or maybe you’d like to figure out the secrets of Zalgo Text or perhaps what characters are in ¯\_(ツ)_/¯ or make a catalog of Emoji in RTF: clui can do it! Head on over to the clui Github page and download the Release if you’d like to try it out on your (Monterey+) Mac, thanks!

Bonus

Since you made it down here, how about a one-liner that will create RTFs of all the Unicode categories? It will likely take several hours and will open a Finder window when finished.

#make RTFs of every Unicode category, this might take a few hours, if you want to cancel close the Terminal window
mkdir ~/Desktop/clui-rtfs; cd ~/Desktop/clui-rtfs; IFS=$'\n'; for category in $(clui -LC | grep Unicode,); do clui -Or -C "$category" > "$category.rtf"; done; open -R .

Determining “iCloud Private Relay” and “Limit IP tracking” status in macOS

September 27, 2022September 27, 2022 brunerd

If you are a Mac admin you might have noticed some Apple plists are more complex than others these days. As evidenced in my post Don’t Be a Jerk, getting the status of Do Not Disturb in Big Sur was a multi-step exercise. Check out this modified code excerpt from doNotDisturb‘s Big Sur handling

#!/bin/sh

#Big Sur DnD status, returns "true" or [blank] (to be run as console user)
dndStatus="$(/usr/libexec/PlistBuddy -c "print :userPref:enabled" /dev/stdin 2>/dev/null <<< "$(plutil -extract dnd_prefs xml1 -o - /dev/stdin <<< "$(defaults export com.apple.ncprefs.plist -)" | 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}" ] && { echo ON; exit 0; } || { echo OFF; exit 1; }

Why is it so complex? Well because with the user preference domain of com.apple.ncprefs there is a base64 encoded plist embedded in the dnd_prefs key and requires some massaging to get it to a state where PlistBuddy can read and then extract the status from the :userPref:enabled key. See it’s just that easy! 😅

In macOS Monterey and higher Apple is now using JSON for Focus status which is great because it can can be parsed much easier (perhaps using my ljt or jpt tools) but sometimes not even that is needed! Sometimes file presence or awking is sufficient to get a reliable result too. See the evolution of doNotDisturb.sh for macOS for the myriad techniques one can use.

Now, here we are at Monterey on the verge of Ventura and not all areas of macOS have seen the JSON light and are still using nested base64-encoded Plist blobs to store the states of new features like iCloud Private Relay but luckily not the per interface setting of Limit IP Tracking.

iCloud Private Relay Status

Now why would you want to know these statuses? Perhaps you have a VPN product that doesn’t work when Private Relay is turned on or if Limit IP Tracking is turned on for a particular interface and you need to alert the user. Additionally maybe there’s an issue if your VPN browser handshake fails when Safari is used, if so see: Determining URL scheme handlers in macOS. Back to the task at hand though let’s turn some prefs inside out and look at iCloud Relay status with iCloudPrivateRelayStatus.sh

#!/bin/bash
: <<-LICENSE_BLOCK
iCloud Private Relay Status Checker - (https://github.com/brunerd)
Copyright (c) 2022 Joel Bruner (https://github.com/brunerd)
Licensed under the MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
LICENSE_BLOCK

#############
# FUNCTIONS #
#############

#include this self-contained function in your script
function iCloudPrivateRelay(){

	#only for Moneterey and up, 11 and under need not apply
	[ "$(sw_vers -productVersion | cut -d. -f1)" -le 11 ] && return 1
	
	#parent pref domain
	domain="com.apple.networkserviceproxy"
	#key that contains base64 encoded Plist within parent domain
	key="NSPServiceStatusManagerInfo"

	#child key within base64 embedded plist
	childKey="PrivacyProxyServiceStatus"

	#get the top level data from the main domain
	parentData=$(launchctl asuser $(stat -f %u /dev/console) sudo -u $(stat -f %Su /dev/console) defaults export ${domain} -)

	#if domain does not exist, fail
	[ -z "${parentData}" ] && return 1

	#export the base64 encoded data within the key as PlistBuddy CF style for grepping (it resists JSON extraction)
	childData=$(/usr/libexec/PlistBuddy -c "print :" /dev/stdin 2>/dev/null <<< $(plutil -extract "${key}" xml1 -o - /dev/stdin <<< "${parentData}" | xmllint --xpath "string(//data)" - | base64 --decode | plutil -convert xml1 - -o -))

	#if child key does not exist, fail
	[ -z "${childData}" ] && return 1

	#match the status string, then get the value using awk (quicker than complex walk, this is sufficient), sometimes written in multiple places
	keyStatusCF=$(awk -F '= ' '/'${childKey}' =/{print $2}' <<< "${childData}" | uniq)
	
	#if we have differing results that don't uniq down to one line, throw an error
	[ $(wc -l <<< "${keyStatusCF}") -gt 1 ] && return 2
	
	#if true/1 it is on, 0/off (value is integer btw not boolean)
	[ "${keyStatusCF}" = "1" ] && return 0 || return 1
}

########
# MAIN #
########

#example - one line calling with && and ||
#iCloudPrivateRelay && echo "iCloud Private Relay is: ON" || echo "iCloud Private Relay is: OFF"

#example - multi-line if/else calling
if iCloudPrivateRelay; then
	echo "iCloud Private Relay is: ON"
	exit 0
else
	echo "iCloud Private Relay is: OFF"
	exit 1
fi

Even though we work really hard to get the plist data extracted we don’t need to walk the entire XML document (you will find PlistBuddy balks at exporting JSON for a number of reasons). Instead we look for the presence of the key name PrivacyProxyServiceStatus and that is sufficient to reliably detect the state. I have 2 versions in my GitHub iCloudPrivateRelayStatus.sh and the minified one line version iCloudPrivateRelayStatus.min.sh

Limit IP Tracking Status

Limit IP Tracking, is a per-interface setting that is on by default, however has no effect unless Private Relay is enabled. For this we will use ljt my Little JSON Tool to retrieve the value from the massaged JSON conversion of com.apple.wifi.known-networks.plist if on WiFi or if on Ethernet .../SystemConfiguration/preferences.plist

#!/bin/bash
: <<-LICENSE_BLOCK
Limit IP Tracking Status Checker - (https://github.com/brunerd)
Copyright (c) 2022 Joel Bruner (https://github.com/brunerd)
Licensed under the MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
LICENSE_BLOCK

#############
# FUNCTIONS #
#############

#include this self-contained function in your script
function limitIPTracking()(

	#only for Moneterey and up, 11 and under need not apply
	[ "$(sw_vers -productVersion | cut -d. -f1)" -le 11 ] && return 1

	#Little JSON Tool (ljt) - https://github.com/brunerd/ljt - MIT License
	function ljt () ( #v1.0.8 ljt [query] [file]
	{ set +x; } &> /dev/null; read -r -d '' JSCode <<-'EOT'
	try{var query=decodeURIComponent(escape(arguments[0]));var file=decodeURIComponent(escape(arguments[1]));if(query===".")query="";else if(query[0]==="."&&query[1]==="[")query="$"+query.slice(1);if(query[0]==="/"||query===""){if(/~[^0-1]/g.test(query+" "))throw new SyntaxError("JSON Pointer allows ~0 and ~1 only: "+query);query=query.split("/").slice(1).map(function(f){return"["+JSON.stringify(f.replace(/~1/g,"/").replace(/~0/g,"~"))+"]"}).join("")}else if(query[0]==="$"||query[0]==="."&&query[1]!=="."||query[0]==="["){if(/[^A-Za-z_$\d\.\[\]'"]/.test(query.split("").reverse().join("").replace(/(["'])(.*?)\1(?!\\)/g,"")))throw new Error("Invalid path: "+query);}else query=query.replace("\\.","\udead").split(".").map(function(f){return"["+JSON.stringify(f.replace("\udead","."))+"]"}).join("");if(query[0]==="$")query=query.slice(1);var data=JSON.parse(readFile(file));try{var result=eval("(data)"+query)}catch(e){}}catch(e){printErr(e);quit()}if(result!==undefined)result!==null&&result.constructor===String?print(result):print(JSON.stringify(result,null,2));else printErr("Path not found.")
	EOT
	queryArg="${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 [ -t '0' ] && echo -e "ljt (v1.0.8) - Little JSON Tool (https://github.com/brunerd/ljt)\nUsage: ljt [query] [filepath]\n  [query] is optional and can be JSON Pointer, canonical JSONPath (with or without leading $), or plutil-style keypath\n  [filepath] is optional, input can also be via file redirection, piped input, here doc, or here strings" >/dev/stderr && exit 0; { errOut=$( { { "${jsc}" -e "${JSCode}" -- "${queryArg}" "/dev/stdin" <<< "$(cat)"; } 1>&3 ; } 2>&1); } 3>&1; fi;if [ -n "${errOut}" ]; then /bin/echo "$errOut" >&2; return 1; fi
	)
		
	#test interface specified or fallback to default interface
	interfaceID=${1:-$(route get 0.0.0.0 2>/dev/null | awk '/interface: / {print $2}')}

	#WIFI: key: PrivacyProxyEnabled, file: /Library/Preferences/com.apple.wifi.known-networks.plist
	#if no error getting WiFi SSID, then we are WiFi
	if networksetup -getairportnetwork "${interfaceID}" &>/dev/null && wifiSSID=$(awk -F ': ' '{print $2}' <<< "$(networksetup -getairportnetwork "${interfaceID}" 2>/dev/null)"); then

		#key name inside plist
		keyName="wifi.network.ssid.${wifiSSID}"

		#oddly this file is only read-able by root
		if [ ! -r /Library/Preferences/com.apple.wifi.known-networks.plist ]; then
			echo "Insufficient preferences to determine WiFi state, run as root" >/dev/stderr
			exit 1
		fi

		#get JSON version, so much easier to get around, convert date and data types to strings
		wifiKnownNetworks_JSON=$(defaults export /Library/Preferences/com.apple.wifi.known-networks.plist - | sed -e 's,<date>,<string>,g' -e 's,</date>,</string>,g' -e 's,<data>,<string>,g' -e 's,</data>,</string>,g' | plutil -convert json -o - -)
		
		#if there is NO entry, then it is active, it is opt-out designed
		PrivacyProxyEnabled=$(ljt "/wifi.network.ssid.${wifiSSID}/PrivacyProxyEnabled" 2>/dev/null <<< "${wifiKnownNetworks_JSON}")
		
		if [ "${PrivacyProxyEnabled}" = "false" ]; then
			return 1
		fi
	#ETHERNET: key: DisablePrivateRelay, file: /Library/Preferences/SystemConfiguration/preferences.plist, 
	else
		#get JSON, easily converts with not data or date types within
		systemConfigPrefsJSON=$(plutil -convert json -o - /Library/Preferences/SystemConfiguration/preferences.plist)
		#get current set UUID
		currentSet=$(echo "${systemConfigPrefsJSON}" | ljt /CurrentSet 2>/dev/null)
		#get value for current default interface of current Location set
		DisablePrivateRelay=$(ljt "${currentSet}"/Network/Interface/${interfaceID}/DisablePrivateRelay  2>/dev/null <<< "${systemConfigPrefsJSON}")

		#if it is TRUE we are Disabled, then we are NOT ON, return fail code
		if [ "${DisablePrivateRelay}" = "1" ]; then
			return 1
		fi
	fi
)

########
# MAIN #
########

if [ ! -r /Library/Preferences/com.apple.wifi.known-networks.plist ]; then
	echo "Insufficient preferences to determine WiFi state, run as root" >/dev/stderr
	exit 1
fi

#use default interface if nothing is specified for argument $1
interface=${1:-$(route get 0.0.0.0 2>/dev/null | awk '/interface: / {print $2}')}

#returns 0 if ON and 1 if OFF, you may supply an interface or it will fall back to the default
limitIPTracking "${interface}" && echo "Limit IP tracking is ON for: ${interface}" || echo "Limit IP tracking is OFF for: ${interface}"

You can specify an interface or it will use the default interface (there’s a good one-liner to use route get 0.0.0.0 to figure that out). plutil is not initially used to convert com.apple.wifi.known-networks.plist to JSON as it will fail due to XML/plist data types like <date> and <data> that do not have JSON equivalents. First we use sed to change them to <string> types then plutil can convert to JSON. After that it’s a cake walk for ljt to get the value and report back. If the interface is not WiFi then /Library/Preferences/SystemConfiguration/preferences.plist has none of those conversion issues. Check out limitIPTrackingStatus.sh and the minified limitIPTrackingStatus.min.sh at my GitHub.

Thanks for reading! P.S. I won’t be at JNUC 2022, better luck next year!

Determining URL scheme handlers in macOS

September 21, 2022October 6, 2022 brunerd

If you’ve worked at a place that uses Outlook for email or Chrome for browsers, knowing is half the battle when it comes to helping out your users. For a long while you could easily determine the URL scheme handlers via the built-in Python or JXA, however things have changed.

For example this JXA used to work brilliantly in Mojave and under:

#!/bin/sh
URLScheme="${1}"

if [ -z "${URLScheme}" ]; then
    echo "Please provide a URL scheme name"
    exit 1
fi

osascript -l JavaScript <<< "ObjC.import('Cocoa'); $.LSCopyDefaultHandlerForURLScheme(\"${URLScheme}\")"

Nothing lasts forever though and all that broke in 10.15 when the result of [object Ref] became the taunting reply. Even if you could hit the juke box like the Fonz and recast the CF value you were getting back into an NS value (thanks for the link Pico), it was a moot point by Big Sur. Apple has killed off about every useful API to figure out what app handles a URL as others have noted.

So after you look at LSCopyDefaultHandlerForURLScheme at the  Dev Docs and then see the scores of other deprecated LaunchServices functions, you might make some joke like “I see dead ~~people~~ APIs” (a la Sixth Sense), but still you wonder: Is there a reliable way to divine this information without resorting to a hacky grep?

Why, yes there is, and it just so happens to use my tool ljt too! While definitely a step up from grepping the output it’s still kinda sad. What was once a few lines must now be accomplished by many more in getDefaultRoleHandler.sh and the minified version getDefaultRoleHandler.min.sh.

#!/bin/sh
: <<-LICENSE_BLOCK
getDefaultRoleHandler - (https://github.com/brunerd)
Copyright (c) 2022 Joel Bruner (https://github.com/brunerd)
Licensed under the MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
LICENSE_BLOCK

#############
# FUNCTIONS #
#############

#use this self-contained function in your script to detect the default role handle
function getDefaultRoleHandler() (
	#provide a URL scheme like: http, https, ftp, etc...
	URLScheme=${1}
	
	#fail quickly
	if [ -z "${URLScheme}" ]; then
		>/dev/stderr echo "No URL scheme specified"
		return 1
	fi

	#Little JSON Tool (ljt) v1.0.7 - https://github.com/brunerd/ljt - MIT License
	function ljt () ( 
	[ -n "${-//[^x]/}" ] && set +x; read -r -d '' JSCode <<-'EOT'
	try{var query=decodeURIComponent(escape(arguments[0])),file=decodeURIComponent(escape(arguments[1]));if("/"===query[0]||""===query){if(/~[^0-1]/g.test(query+" "))throw new SyntaxError("JSON Pointer allows ~0 and ~1 only: "+query);query=query.split("/").slice(1).map(function(a){return"["+JSON.stringify(a.replace(/~1/g,"/").replace(/~0/g,"~"))+"]"}).join("")}else if("$"===query[0]||"."===query[0]||"["===query[0]){if(/[^A-Za-z_$\d\.\[\]'"]/.test(query.split("").reverse().join("").replace(/(["'])(.*?)\1(?!\\)/g,"")))throw Error("Invalid path: "+query);}else query=query.replace("\\.","\udead").split(".").map(function(a){return"["+JSON.stringify(a.replace("\udead","."))+"]"}).join("");"$"===query[0]&&(query=query.slice(1,query.length));var data=JSON.parse(readFile(file));try{var result=eval("(data)"+query)}catch(a){}}catch(a){printErr(a),quit()}void 0!==result?null!==result&&result.constructor===String?print(result):print(JSON.stringify(result,null,2)):printErr("Path not found.");
	EOT
	queryArg="${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 [ -t '0' ] && echo -e "ljt (v1.0.7) - Little JSON Tool (https://github.com/brunerd/ljt)\nUsage: ljt [query] [filepath]\n  [query] is optional and can be JSON Pointer, canonical JSONPath (with or without leading $), or plutil-style keypath\n  [filepath] is optional, input can also be via file redirection, piped input, here doc, or here strings" >/dev/stderr && exit 0; { errOut=$( { { "${jsc}" -e "${JSCode}" -- "${queryArg}" "/dev/stdin" <<< "$(cat)"; } 1>&3 ; } 2>&1); } 3>&1; fi;if [ -n "${errOut}" ]; then /bin/echo "$errOut" >&2; return 1; fi
	)

	#in case being run as root get the current console user
	consoleUserHomeFolder=$(sudo -u "$(stat -f %Su /dev/console)" sh -c 'echo ~')
	#get the LaunchServices LSHandlers JSON of the console user
	launchServicesJSON=$(launchctl asuser "$(stat -f %u /dev/console)" sudo -u "$(stat -f %Su /dev/console)" plutil -extract LSHandlers json -o - "${consoleUserHomeFolder}"/Library/Preferences/com.apple.LaunchServices/com.apple.launchservices.secure.plist)

	#loop through JSON and try and find matching URLScheme within
	for ((i=0;;i++)); do
		#if we are at the END of the array or nothing exists bail
		if ! ljt "/$i" <<< "${launchServicesJSON}" &>/dev/null; then
			return 1
		elif [ "$(ljt "/$i/LSHandlerURLScheme" <<< "${launchServicesJSON}" 2>/dev/null)" = "$URLScheme" ]; then
			#run query, print result, errors go to /dev/null, if ljt fails to find something return non-zero
			if ! ljt "/$i/LSHandlerRoleAll" <<< "${launchServicesJSON}" 2>/dev/null; then
				#error
				return 1
			else
				#success
				return 0
			fi
		fi
	done
	
	#if we are here, we did NOT find a match
	return 1	
)

########
# MAIN #
########

getDefaultRoleHandler "$@"

We use plutil to extract the contents of the LSHandlers key as JSON from ~/Library/Preferences/com.apple.LaunchServices/com.apple.launchservices.secure.plist then we iterate over the array using a for loop and ljt until it finds a matching LSHandlerURLScheme and then it prints out the value of LSHandlerRoleAll. The operation and output are simple and no nonsense. Give it a URL scheme and it gives you the Bundle ID of the app which will open it or if not found, nothing. (Note: mailto will be blank by default, only after switching to another client will it return a result)

You can use this function in your scripts. Head over to my GitHub to download either getDefaultRoleHandler.sh or the minified getDefaultRoleHandler.min.sh. Perhaps you need to alert a user to change their application preferences after installation of an email client or web browser. You can use my shui function to alert them, btw. But I’m not getting into setting handlers via script in this post, writing to the plist can be a trick but the real trick is getting LaunchService to read from that plist (without asking for a reboot or logout, ick)! So for now “Knowing Is Half The Battle™”

Post Posting Update

Armin Briegel, over at the wonderful wealth of aggregated MacAdmin knowledge that is scriptingosx.com, is always kind enough to post my articles and this very one appears in the Week of 2022-09-22. Along with this post is a link to a MacAdmins Slack thread where he kindly provided some JXA that returns the file path for a URL scheme handler (vs. the above Bundle ID), then Pico jumped in and crushed it down to a 1 liner! I’ve added the thinnest of function wrappers over top:

#!/bin/sh
#getDefaultRoleHandlerPath - Joel Bruner with 🙏 thanks to a couple stalwarts of the MacAdmin Slack Armin Briegel and Pico

function getDefaultRoleHandlerPath()(urlScheme="${1}"; [ -z "${urlScheme}" ] && return 1; osascript -l 'JavaScript' -e "ObjC.import('AppKit'); $.NSWorkspace.sharedWorkspace.URLForApplicationToOpenURL($.NSURL.URLWithString('${urlScheme}:')).path.js")

getDefaultRoleHandlerPath "$@"
exit $?

So it seems Apple has spared an API in AppKit’s NSWorkspace by the name of URLForApplicationToOpenURL, which has been around since macOS 10.6! Perhaps when I get over my trust issues with JXA, I’ll explore these APIs to see what else might be useful. For now though this does the trick of returning a filepath (not Bundle ID)

Listing All Schemes for User

I got a question about listing all the schemes a user might have registered. This is an example one-liner (granted jpt is embedded in the script or installed locally) to be run by the current user. If you want to run as root, cannibalize getDefaultRoleHandler.sh for code)

jpt -T '$.*.LSHandlerURLScheme' <<< $(plutil -extract LSHandlers json -o - ~/Library/Preferences/com.apple.LaunchServices/com.apple.launchservices.secure.plist)

The -T option will output text (vs. an array of double quoted JSON strings) .* looks at every array member to print out every LSHandlerURLScheme entry for the current console user. It’ll look something like this

brunerd tools summer 2022 updates

July 10, 2022July 10, 2022 brunerd

Hey there, it’s summer 2022 and I wanted to share some updates on my shell tools for Mac admins.

No breaking changes or anything huge, but some nice incremental improvements all the same. When the JSONPath spec is finalized I’ll give jpt a more considerable under the hood improvement. For now though, I’m pretty happy with tweaking their behaviors to act like you’d expect (print help and exit if no input detected), to get out of your way when you need to debug your scripts (xtrace is now disabled inside them) and to try to understand what you mean when you ask them a question (key path queries now accepted). Because the tools and technologies we make should serve us, not the other way around. I hope these tools can save you time, energy, sanity or all the above!

• jpt the “JSON Power Tool” has been updated to v1.0.2 with all the nice additions mentioned. If you don’t know already jpt can parse, query, and modify JSON every which way. It can be used as both a standalone utility as well as a function to be embedded into your shell scripts, without any other dependencies.

• ljt the “little JSON tool” is jpt‘s smaller sibling weighing in at only 2k. While it lacks the transformational powers of jpt it can easily pluck a value out of JSON up to 2GB big and output results up to 720MB. It has been updated to v1.0.7 because dang it, even a small script can have just as many bugs as the big ones. Sometimes more if you’re not careful!

Both jpt and ljt now accept ye olde NextStep “keypath” expressions to help win over masochists who might still use plutil to work with JSON! 😁 (I kid, I kid!)

• jse, the “JSON string encoder” does this one thing and does it well. It can be used in conjunction with jpt when taking in arbitrary data that needs encoding only. It’s a svelte 1.4k (in minified form) and runs considerably faster that jpt, so it’s ideal for multiple invocations, such as when preparing input data for a JSON Patch document. v1.0.2 is available here

• shui lets you interact with your users with AppleScript but in the comfort of familiar shell syntax! You don’t need to know a line of AppleScript, although it does have the option to output it if you want to learn. Save time, brain cells and hair with shui, while you keep on trucking in shell script. It has been updated to v20220704.

P.S. All these tools still work in the macOS Ventura beta 😅

ljt, a little JSON tool for your shell script

February 22, 2022February 25, 2022 brunerd

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! 🤓 The minified version is mere 1.2k and offers a bit more security and functionality than a one-liner.

ljt features:
• Query using JSON Pointer or JSONPath (canonical only, no filters, unions, etc)
• Javascript code injection prevention for both JSON and the query
• Multiple input methods: file redirection, file path, here doc, here string and Unix pipe
• Output of JSON strings as regular text and JSON for all others
• 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)
• 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!