In the first of a series of AppleScript tutorials, this post explains why you might want to consider learning AppleScript.
What’s the use?
If you’re not sure whether you want to invest time in learning AppleScript, this post is for you. Here I’ll outline four good reasons to learn AppleScript. I’m sure they’re not the only ones, but they’re the main ones that come to my mind as a daily user of the language. If, after reading this post, you want to give it a try, be sure to follow this series, as we’ll be quickly moving on with hands-on examples and detailed explanations that will rapidly turn you into an AppleScript power user! At the end of this post, I’ll briefly discuss tools, so that you’re ready to get started when the next in this series, User In, User Out, is published.
First of all, AppleScript can interact with other applications. That means it can get one app to perform a function and pipe the result to another app to perform a different function that the first app didn’t have. There’s no limit to the number of apps and functions you can chain together in this way (other than your computer’s resources). Why would you want to chain apps together like that?
To achieve things that none of those apps can do on their own.
Imagine this scenario (scripts for this appear later in this series of posts): Suppose you run a small business and customer orders come in via email. With an AppleScript, you can have those emails automatically scanned, the customers’ order details extracted, and your Excel or Numbers spreadsheet updated accordingly. You could then have the product details forwarded to another person (Packaging?) and the customer details forwarded to a third (Marketing?). Your script could tell Word, or Pages, to print out a label, and tell Mail to now send an automated response back to the customer. There is no one program on your computer that can accomplish all that, but you can, with AppleScript.
Once set up, none of this requires any interaction on your part. You build the script, test it, and add it as a Mail rule. The rest happens automatically when the mail arrives in your Inbox; you don’t need to monitor it. You can go on holiday. This ability to automate is what makes AppleScript so unique.
AppleScript’s ability to chain or pipe application functions together is similar to the Unix command line ability to pipe utilities together, only it allows you to do it with full-blown applications. But you can use it to connect those applications to command line utilities, too. This is the second thing that makes AppleScript unique: integration across the entire macOS environment. You can even chain it to other programming languages.
For example, I could have AppleScript run some Python code, take the result and run that through a Perl script, and take the result of that and display it to the user (or myself) in a dialog box or notification (or send an email, or a Chat message, etc). And I can do that without having to mess about worrying how to create graphical user interface elements like you might do with Tcl/Tk (if you know what that is; if you don’t, forget it!).
The relationship between AppleScript and the shell is symbiotic. If you’re a shell diehard, you’ll be happy to know that you can actually create and execute AppleScripts in
.sh files without ever going near an AppleScript editor.
AppleScript can not only harness the power of other scripting languages, it can harness the power of macOS itself. The AppleScript-ObjectiveC bridge means you could, if you wanted to – and many programmers do – create full on native macOS Cocoa apps without ever getting into the intricacies of Xcode projects and workspaces. You can even code sign your AppleScript apps from within the script editor.
Finally, AppleScript can drive the user interface and even drive apps that haven’t been specifically made to support AppleScript. If you find yourself repeatedly doing the same actions in the UI to achieve a task, you can cut-out the middle-man (you!) and tell AppleScript to click those buttons, move those windows or copy that text from Safari and paste it into Pages instead of laboriously and repeatedly doing it yourself. This creates an eery effect not unlike those old-time pianolas.
Look no hands!
Where’s the catch? To achieve the level of automation and time-saving we’ve been discussing, you’re going to have to invest some time up front learning how to script. It won’t always be easy, and you won’t always be happy that it’s not easy, but that’s the price of investing in learning anything.
If you’re ready to learn this amazing, unique language, let’s get tooled up!
I’ll keep this short. You can learn AppleScript the hard way using the built-in Script Editor, or you can learn AppleScript the easier way by using the free 3rd-party editor Script Debugger.
Script Debugger gives you a full-featured trial for 20 days, and after that if you don’t want to buy it you lose some of the more advanced features but you can use the rest indefinitely anyway. It works in rather the same way as BBEdit’s trial does, if you’re familiar with that.
If you save scripts in Script Debugger (so long as they’re not debug scripts, more on that later), you can run (and edit) them in Script Editor and vice versa. In other words, you’re not locked in to a proprietary tool.
I’m not even going to consider that you’d choose to learn AppleScript the hard way since the easier way is free, so all the examples in this series of posts will use Script Debugger. However, unless otherwise marked as SD-only or SD-paid-only, you can do all of the examples in the series in either tool.
Don’t worry, at this point, about how to use either Script Editor or Script Debugger. We’ll get into that in the next post: hello, applescript 2: User In, User Out. Follow Applehelpwriter to be notified when a new post is published.
The problem with the simple alert I demonstrated last time is that it only hangs around for a second or two (much less than a Folder Action alert, which takes a couple of minutes to time out). In this updated function, it now also writes a list of the file changes to a (by default) file on the Desktop. The write is an append: if the file doesn’t exist it will create it before writing; if it does exist, it will append the latest changes and date to the file. This way, even if you miss the alert, you’ll always have a record of what files have been added, deleted or modified in your watched folder.
In this example, the folder being watched is ~/Library/LaunchAgents since we want to be aware of any adware, malware or other unsavoury processes being surreptitiously added by, for example, apps we download from the internet. Although there are, of course, many legitimate reasons for apps placing items in here, this folder is prime real estate for attackers as it is one of the locations that can launch processes at log in time without the user’s interaction (or knowledge).
Here’s the code, also available from my pastebin here. A code walkthrough follows.
function writeStringToFileWithMode(aString, aPath, aMode)
this_file = io.open(aPath, aMode)
local str = "Launch Agents folder was modified on " .. os.date() .. " :\n\t"
local this_path = os.getenv("HOME") .. "/Desktop/LaunchFolderModified.txt"
local ignore = "DS_Store"
local count = 0
for _,file in pairs (files) do
count = count + 1
i = string.find(file, ignore)
if not i then
str = str .. file .. "\n\t"
if count == 1 then
str = "\n"
str = str .. "\n"
writeStringToFileWithMode(str, this_path, "a")
if string.len(str) > 2 then
hs.alert.show("Launch Agents folder was modified.")
local aWatcher = hs.pathwatcher.new(os.getenv("HOME") .. "/Library/LaunchAgents/", myFolderWatch):start()
The first function, ‘writeStringToFileWithMode’ is just a convenience function. Hopefully the clue is in the name. The ‘aMode’ parameter is either “w” for write(over) or “a” for write(append).
The myFolderWatch function starts off by declaring some local variables.
‘str’ includes the initial line that we want to write to our output file and interpolates the time of the change by calling os.date().
‘this_path’ defines the path that we want to write our list of file names too.
The ‘ .. ‘ in both these assignments is a string concatenator (i.e., like ‘&’ in AppleScript or ‘stringByAppendingString’ in Obj-C).
‘ignore’ is a string that will help us to exclude .DS_Store files from triggering the alert or appearing in the list of file changes.
The ‘count’ variable is an internal var we need in order to eliminate .DS_Store changes when it’s the only change. Lua doesn’t have an easy way to count entries in tables, so we bascially iterate a variable each time through the loop to achieve the same effect.
After that, we have the ‘for’ loop. For loops in Lua are weird (at least for me), as you’ll see that they have this structure for
a,b in pair (aPair). I won’t go into why, other than to say its a result of Lua’s table data structure. The
'_' here is just a dummy variable for the first parameter. The ‘files’ in parentheses are the list of file names (not file specifiers, you AppleScripters!) that were added, deleted, or modified in the watched folder.
The loop begins by incrementing the count, then checks for the ignore file (.DS_Store). If the ignore file is not found, we then append the filename to the str variable.
If it is found, we check the count. If the count is ‘1’ (i.e., the only change was .DS_Store) we discard the entire str var and replace it with new line character. If the count is more than 1 we don’t do anything to ‘str’. We just ignore adding anything to it all.
At the end of the for loop we add another new line to the string just so our outputted text file looks nice and neat.
Then we call the write function mentioned above, passing ‘a’ (append) for the mode.
Finally, we fire the UI alert on the condition that the string has got more than 2 characters in it (if it didn’t it was just the “\n\n” string from ignoring the DS.Store file).
After the function definition, the aWatcher variable sets up the watcher on the path we want to observe and tells the watcher to start monitoring. It tells the watcher to call our myFolderWatch function when anything happens.
Deploying the code
After editing the config file, remember there’s two steps: i. save the file and ii. choose ‘Reload Config’ from the Hammerspoon menu.
More details are available about Hammerspoon from the official site here.
My beginners guide with the original simple watcher function is here.
Is it me, or is AppleScript experiencing something of an Indian Summer? It seems everywhere I go, people are talking more about macOS automation, AppleScript and even Apple’s curious hybrid syntax AppleScriptObjC (ASObjC).
Of course, some people have suffered miserably at the hands of AppleScript in the past, and even though the thought of scripting with access to Cocoa APIs through Objective-C is tempting, they fear the AppleScript side of it.
If that’s you, bear in mind that AppleScriptObjC isn’t really “AppleScript + Objective-C” at all. It is actually just a dialect of Objective-C that will be accepted in the (Apple)Script Editor and can be run by an instance of the AppleScript component. In plainer English, you can use Objective-C in an AppleScript without any AppleScript whatsoever!
The point of doing so would be that one could package Objective-C code in a .scpt file (or scptd bundle or AppleScript .app), and also mix whatever scripting language you prefer with calls to Cocoa’s APIs.*
The problem that using ASObjC presents anyone familiar with Objective-C is how to translate ‘pure’ Objective-C into the dialect that Script Editor (and other applescript runners like FastScripts, Keyboard Maestro, Automator, etc) can understand. If you use LateNight Software’s Script Debugger for scripting, you’ll already know that the work is done for you by the app’s built-in code completion. If you’re battling on in Apple’s default Script Editor, you’ll need to do the translation manually.
By way of example, then, here’s some original Objective-C, and below it, a translation that would work in Script Editor:
NSString *aString = @"hello";
NSString *bString = @" world";
aString = [aString stringByAppendingString:bString];
NSUserNotification *notif = [[NSUserNotification alloc] init];
notif.informativeText = aString;
[[NSUserNotificationCenter defaultUserNotificationCenter] deliverNotification:notif];
set aString to NSString's stringWithString:"hello"
set bString to NSString's stringWithString:" world"
set aString to aString's stringByAppendingString:bString
set notif to NSUserNotification's alloc's init
set notif's informativeText to aString
NSUserNotificationCenter's defaultUserNotificationCenter()'s deliverNotification:notif
As you can see, there’s a direct 1-to-1 correspondence, with the 6 statements in Objective-C paralleled by the 6 statements in AppleScriptObjC.
The main peculiarity is the use of possessive word forms and that variable attribution is done by using
"set X to Y" rather than
"X = Y". Type declaration is done via the idiom
'set <var> to <NSObject>'s <class init method>', which returns an instance of the object just as it would normally. You call instance methods by putting the instance in front of the method just as you would in regular Objective-C (e.g, see line 3 of the examples).
As you can see in the screenshot below showing Xcode and Script Editor, they work in the same way. You’ll notice in Script Editor there is a
'use' statement (equivalent to Objective-C’s ‘import’), and there’s also a whole load of property statements. These latter are peculiar to the ASObjC translation, and don’t have a counterpart in pure Objective-C. All you need to know about these is for each kind of Objective-C object you want to use (NSString, NSArray, whatever*), you’ll want a property statement for it at the beginning of the script. The statement always has the same form:
property <NSObject> : a reference to current application's < NSObject>
I think the best way to think of ASObjC was recently summed up by Sal Saghoian, when he said that ASObjC is “…the ultimate duct tape. You can do anything you want with ASObjC. You own the computer.”
*not all Cocoa frameworks nor all Objective-C objects can be bridged to, but pretty much all the most useful ones are available.
I recently discovered a neat little extra automation tool on top of the familiar ones of AppleScript, Automator, and script runners like FastScripts and Keyboard Maestro. Meet Hammerspoon, which differs significantly in not using Apple Events to do many of its automation tasks. Instead, Hammerspoon bridges directly to Apple APIs using the lua scripting language, and that allows you to do some interesting things.
Here’s a good example. One of the ‘danger zones’ on your mac – by which I mean one of the favourite places for adware, malware and other assorted badwares to infect – is your LaunchAgents folders. Apps like my DetectX and FastTasks 2 keep an eye on these areas by design, warning you in the Changes and History logs when files have been added or removed from them – but Hammerspoon can add an extra little ‘canary’ warning for you too. With only a few lines of code in Hammerspoon’s config file, you can set up an alert that will fire whenever the LaunchAgents folder is modified.
It has been possible to rig up something similar for a long time with Apple’s built-in Folder Actions, but there’s a couple of reasons why I prefer Hammerspoon for this task. One, despite Apple’s attempt to improve Folder Actions’ reliability, I’m still not convinced. I get inconsistent reports when asking System Events to check whether Folder Actions is enabled even on 10.11 and 10.12. Second, Folder Actions is limited in what it will respond to. By default, only if an item is added. With a bit of effort, you can rig it up to watch for items deleted, too, but that’s pretty much it. With Hammerspoon, it’ll alert you whenever the folder or its contents are modified in any way whatsoever. The final reason for preferring Hammerspoon for this particular task is ease of use. It really is as simple as pasting this code into the config file:
hs.alert.show("Launch Agents folder was modified")
hs.alert.show("Canary folder was modified")
local aWatcher = hs.pathwatcher.new(os.getenv("HOME") .. "/Library/LaunchAgents/", myFolderWatch):start()
local bWatcher = hs.pathwatcher.new(os.getenv("HOME") .. "/_Acanary/", canaryFolderWatch):start()
And what’s the config file you ask? Nothing complicated! Just launch Hammerspoon, click its icon and choose ‘open config’.
That will launch your default text editor, and all you do is paste your code into there, save it (no need to tell it where, Hammerspoon already knows) and then go back to the Hammerspoon icon and click ‘Reload config’. That’s it. Less than a minute’s work!
There’s a lot, lot more you can do with Hammerspoon, so if you’re interested head off and check out the Getting Started guide. One of the nice things is that you can even call AppleScripts with it, so you really do have a world of automation options to choose from!
Here’s a short video showing some of the differences between Apple’s own Script Editor and my DisplayDroid.
If you haven’t got 5 minutes, the highlights include:
DisplayDroid shows result of each line of the script
DisplayDroid offers more informative error messages
DisplayDroid allows you to set a breakpoint on any line in your script
DisplayDroid lets you step through the script line by line