Category: ljt

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

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

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

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

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!