TweetFollow Us on Twitter

Mac in the Shell: Automation Potpourri

Volume Number: 23 (2007)
Issue Number: 06
Column Tag: Mac in the Shell

Automation Potpourri

Shell and GUI scripting come together

by Edward Marczak

Introduction

Last month, I gave an overview of some commands that I felt just didn't have the coverage and documentation that they deserved. The theme this month is commands that enable us to tie our shell scripts into the GUI. While I'm an advocate for good ole bash scripting, there are times when it's easier or better for some reason to tie in a GUI app. Think about scripting Safari, Address Book or Excel using familiar utilities in the shell. What about incorporating an AppleScript into a workflow with data piping in and out of it? If that sounds like a panacea, read on!

AppleScript

Under OS X, AppleScript is the clear reach-into-just-about-anything scripting technology. Why choose bash scripting over AppleScript? Let me enumerate some ways:

Portability.

Existing stock snippets.

Speed.

Familiarity.

Ability to do things that AppleScript alone can't do.

Since the addition of 'do shell script' to AppleScript, there's little we can't coerce it into doing. This allows us to call a shell script from within AppleScript and return the results. What a powerful combination. That's great when the logic and script itself lie mainly in AppleScript. However, what if the situation were reversed? What if you have a lengthy shell script that needs to utilize an AppleScript? Enter 'osascript'.

osascript allows us to execute AppleScript commands and scripts from a standard shell. In the it's-getting-better-all-the-time category, as of 10.4 ("Tiger"), you can pass arguments into osascript, and AppleScript can pick them up in the 'argv' variable. It can run simple AppleScript commands all in one shot, or, it can run a script file. Let's see an example:

osascript -e "tell application \"Safari\" to launch"

That's about as simple as it gets. Standard shell conventions apply, so make sure you escape quotes and other special characters. The "-e" flag is used to denote a 'command,' or line in the script. Scripts that need multiple lines need multiple "-e" flags. For example, look at this command:

osascript -e 'tell application "Finder"' -e 'make new Finder window to folder "Applications" of startup disk' -e 'end tell'

Three lines of AppleScript, three "-e" switches. Note the use of single quotes here to avoid the pain of escaping double quotes. Naturally, you probably want to put lengthy or complex scripts into their own file. So, the previous example could have been its own file:

new_app_win.scpt
tell application "Finder"
   make new Finder window to folder "Applications" of startup disk
end tell

This could then be invoked as "osascript new_win_app.scpt". Pretty handy. (Of course, this contrived example could be replicated easily in the shell alone as "open /Applications").

The Real Power

So, rather than come up with anything too contrived, let's explore where you may really use this. Let's take a look at a script that, in part, I really use.

Once upon a time, I had a script that mashed and mangled a bunch of data nightly. It would get this data from various data sources: MySQL, text files and the web. For the web sources, I simply used curl to fetch the data I needed as CSV files. Well, one day, my script stopped working. Why? Security. The web site in question required a certain login sequence, and tokens were generated for each form and page load so they couldn't be forged. Consequently, I needed a 'real' browser to do this part. Safari and AppleScript to the rescue. I was able to keep my shell script in place and largely untouched. I did need to swap out the curl calls, of course, and replace them with osascript auto_web_dl.scpt. The AppleScript file scripts Safari to load pages, click links and save the resulting file. Let's dissect:

auto_web_dl.scpt

on run argv
   tell application "Safari"
      activate
      -- Initial load
      set URL of document 1 to "http://some.example.com/page/"
      repeat until do JavaScript "document.readyState" in document 1 is "complete"
      end repeat
      delay 5
      
      -- click the link
      set URL of document 1 to do JavaScript "documents.links[3].href" in document 1
      repeat until do JavaScript "document.readyState" in document 1 is "complete"
      end repeat
      delay 5
      
      -- load the reports verification page
      set URL of document 1 to "https://setup.example.com/¬
accounting/check? done=http%3a//some.example.com%2Faccouting%2Freports" repeat until do JavaScript "document.readyState" in document 1 is "complete" end repeat delay 5 -- fill in the values do JavaScript "document.getElementById('realm').value = 'ap'" in document 1 do JavaScript "document.getElementById('history').value = '1'" in document 1 do JavaScript "document.settings_form.submit()" in document 1 repeat until do JavaScript "document.readyState" in document 1 is "complete" end repeat delay 5 -- get the reports page set URL of document 1 to "http://some.example.com/accounting/¬
cur_report?export=true&level=sub" repeat until do JavaScript "document.readyState" ¬
in document 1 is "complete" end repeat delay 10 -- save the contents set theSaveName to "acct_nightly.csv" set theSavePath to (path to desktop folder as string) & theSaveName tell application "Safari" save document 1 in file theSavePath end tell tell application "Finder" if file (theSavePath & ".download") exists then set name of file (theSavePath & ".download") to theSaveName end if end tell end tell end run

(A big thank you to Ben Waldie from automatedworkflows.com for teaching me how to get Safari to save a plain text document! Not being an AppleScript person by nature, I just couldn't nail it down).

So, yes, this took a little knowledge of JavaScript and Document Object Model. Not terribly esoteric, but if you're solely a bash scripting person, this may be a bit foreign. Now, my shell script remained in bash, and runs as a nightly cron job that delivered reports to company executives. The abridged version is now this:

#!/bin/bash
# Grab initial MySQL data
mysqldump -u db_user...> /data/table1.csv
# Grab web data
curl —LO http://financialinfo.example.com/stocks.php?id=2345
# Grab accounting data
osascript auto_web_dl.scpt
# Process results
/usr/local/bin/data_process /data

Further Interaction

More than just being able to call AppleScript from the shell, there are several ways to pass variables between the two environments. The first is a natural extension of what you know from bash. Simply put the bash variable on the command line:

$ osascript -e 'tell application "Finder"'¬ 
-e "display dialog \"Hello, $USER\"" -e 'end tell'

This will display a dialog box in the Finder containing the name of the currently logged-in shell user. Notice also, that when this is run, osascript returns values to the shell. Again, of course, you can use or discard these values as the situation dictates. Note that this is a valid way to pass data out of AppleScript and back into the shell.

Look at the possibilities this opens up! Take, for example, the following script:

#!/bin/sh
for user in $(dscl /LDAPv3/127.0.0.1 -list /Users)
do
        ma=$(dscl /LDAPv3/127.0.0.1 -read /Users/$user mail)
        osascript -e "tell application \"System Report\" process $ma"
done

Here, we use bash and dscl to pull all users from Open Directory and then feed each of those into the fictitious application "System Report".

Another way to pass data between the two environments is via environment variables. AppleScript will happily reach out and grab environment variables from a shell using the system attribute variable. Let's say each user on the system has environment variable defined for their favorite color called, "my_color ". Without passing it in as an argument, AppleScript can access it like this:

set favorite_color to system attribute "my_color"

You can then go on and have AppleScript make decisions based on your new variable.

Finally, you can pass and values into the AppleScript as arguments. Given the following AppleScript:

on run argv
   tell application "System Events"
      repeat with currentArg in (every item of argv)
         display dialog currentArg
      end repeat
   end tell
end run

It could be called like this:

osascript asarg.scpt mike bill joe

This will cause three dialog boxes to appear, each containing one of the arguments passed in.

The trick here is wrapping everything in the "on run argv" block. Since argv is an AppleScript list, you can access any element directly. For example, argument one is simply, "item 1 of argv".

In Conclusion

I hope this short, but important topic, stirs some ideas in your head. These techniques truly make the scripting environment boundless. While there are many, many cases where you can script a workflow entirely in bash, or entirely in AppleScript, they are also many reasons to integrate the two. I talk consistently about remote management and troubleshooting of Macintosh systems. This is yet another great weapon in your arsenal. With only command line access, you can now launch applications, interact with them, and the user sitting at the console.

Using osascript also allows AppleScript into places that it is usually not allowed in. Think about a user interacting with a web page, and one of their actions runs an AppleScript. You can also use osascript to interact with users at important times. You can display a dialog box prior to running a CPU intensive cron job. This trick also comes in handy to alert users of actions being taken during login hooks.

One thing to note, though: while the data coming out of osascript is on stout, osascript has no concept of stdin. So, you need to use one of the techniques covered here to get data into an AppleScript. You just can't pipe your data in. (OK, in all fairness, you could get data into an AppleScript by reading a file or through sockets, etc. — just not via stdin!).

Don't forget: interaction with osascript isn't just limited to bash and its constructs. Take a look at this great example from Apple's own, "AppleScript Overview":

osascript -e 'tell app "Address Book" to get the name¬ 
of every person' | perl -pe 's/, ¬
/\n/g'| sort | uniq —d

This one liner will output duplicate entries from your address book. While I'm sure this could have been scripted entirely in AppleScript, it's unlikely that it would have been as concise or elegant as this one-liner.

The point is simple: mix and match as needed to solve the problem at hand. You have many varied tools at your disposal, each with particular strengths, advantages and weaknesses.

Media of the month: It's Johnny Cash month! If you've never listened to, "At Folsom Prison", do yourself a favor and experience it. If you know virtually nothing of the man, go rent "Walk the Line".


See you next month, post WWDC!

Ed Marczak owns and operates Radiotope, a technology consultancy specializing in automating business processes and enabling communications between employees and clients. Communicate at http://www.radiotope.com.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

calibre 2.69.0 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
Evernote 6.9.1 - Create searchable notes...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
jAlbum Pro 13.5 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. You can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly... Read more
jAlbum 13.5 - Create custom photo galler...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results - Simply drag and drop photos into groups, choose a design... Read more
Google Chrome 53.0.2785.143 - Modern and...
Google Chrome is a Web browser by Google, created to be a modern platform for Web pages and applications. It utilizes very fast loading of Web pages and has a V8 engine, which is a custom built... Read more
Chromium 53.0.2785.143 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 53.0.2785.143: [Security Fix] High CVE-2016-... Read more
QuickBooks 2015 16.1.7.1524 R8 - Financi...
Save 20% on QuickBooks Pro for Mac today through this special discount link QuickBooks 2015 helps you manage your business easily and efficiently. Organize your finances all in one place, track... Read more
Sierra Cache Cleaner 11.0.1 - Clear cach...
Sierra Cache Cleaner is an award-winning general purpose tool for macOS X. SCC makes system maintenance simple with an easy point-and-click interface to many macOS X functions. Novice and expert... Read more
Default Folder X 5.0.7 - Enhances Open a...
Default Folder X attaches a toolbar to the right side of the Open and Save dialogs in any OS X-native application. The toolbar gives you fast access to various folders and commands. You just click on... Read more
Safari Technology Preview 10.1 - The new...
Safari Technology Preview contains the most recent additions and improvements to WebKit and the latest advances in Safari web technologies. And once installed, you will receive notifications of... Read more

Pumped BMX 3: Beginner tips and tricks
There’s a whole lot more to Pumped BMX 3 than meets the eye. Your goal is to perform a wide array of sweet flips and tricks, but that’s easier said than done. It takes well practiced timing and coordination, and the game doesn’t really explain that... | Read more »
Cybird’s latest release - BFB Champions...
Launched in the UK in early September, BFB Champions’ newest update is loaded with great new features, and looks set to outshine the original version by taking it out of soft launch and giving it a new lease of life. | Read more »
3 apps to boost your focus
As someone who works from home, my workspace is a minefield of distraction. Cats, tasty snacks, the wind blowing past my window, that cleaning that I suddenly can’t put off any longer. If I let distraction takes its course, I find that soon half... | Read more »
Pumped BMX 3 (Games)
Pumped BMX 3 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: The final instalment of the smash hit #1 rated BMX game is here! Following on from the insane success of Pumped BMX 2, Pumped 3... | Read more »
4 games like Burly Men at Sea to inspire...
Burly Men at Sea is out today and it looks a treat. It tells the tale of three Scandinavian fishermen who leave the humdrum of their daily lives to go exploring. It’s a beautiful folksy story that unfurls as you interact with the environment... | Read more »
3 reasons you need to play Kingdom: New...
Developed by a tag team of indie developers - Thomas "Noio" van den Berg and Marco "Licorice" Bancale - Kingdom is a vibrant medieval fantasy adventure that casts players as a king or queen who must expand their empire by exploring the vasts lands... | Read more »
JoyCity have launched a brand new King o...
Great news for all of you Game of Dice fans out there - JoyCity have just released a brand new limited edition pack with a really cool twist. The premise of Game of Dice is fairly straightforward, asking you to roll dice to navigate your way around... | Read more »
Burly Men at Sea (Games)
Burly Men at Sea 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Burly Men at Sea is a folktale about a trio of large, bearded fishermen who step away from the ordinary to seek adventure. | Read more »
3 tips for catching the gnarliest waves...
Like a wave breaking on the shore, Tidal Rider swept its way onto the App Store charts this week settling firmly in the top 10. It’s a one-touch high score-chaser in which you pull surfing stunts while dodging seagulls and collecting coins. The... | Read more »
The beginner's guide to destroying...
Age of Heroes: Conquest is 5th Planet Games’ all new turn-based multiplayer RPG, full of fantasy exploration, guild building, and treasure hunting. It’s pretty user-friendly as far as these games go, but when you really get down to it, you’ll find... | Read more »

Price Scanner via MacPrices.net

CAZE Annouces New Zero 5 Case for Jet Black i...
Hong Kong basd CAZE has announced Zero 5 case for iPhone 7/ 7 Plus, one of the world’s thinnest clear hard cases, measuring just 0.5 millimeters. CAZE has been producing and improving the Zero 5... Read more
Nest Egg Inventory App for iOS Offers Conven...
Campbell, California based Winprogger LLC has announced the release and immediate availability of Nest Egg – Inventory 4.1.22, an important update to their easy-to-use, yet comprehensive inventory... Read more
Factor4, LLC Launches Apple iOS and Android G...
Factor4, LLC, which offers gift and loyalty services to the SMB marketplace, has released free mobile applications that enable merchants to process via all Apple and Android devices. The Apple and... Read more
15-inch Retina MacBook Pros on sale for $200...
B&H Photo has 15″ Retina Apple MacBook Pros on sale for $200 off MSRP. Shipping is free, and B&H charges NY tax only: - 15″ 2.2GHz Retina MacBook Pro: $1799 $200 off MSRP - 15″ 2.5GHz Retina... Read more
Apple refurbished iMacs available for up to $...
Apple has Certified Refurbished 2015 21″ & 27″ iMacs available for up to $350 off MSRP. Apple’s one-year warranty is standard, and shipping is free. The following models are available: - 21″ 3.... Read more
Check Apple prices on any device with the iTr...
MacPrices is proud to offer readers a free iOS app (iPhones, iPads, & iPod touch) and Android app (Google Play and Amazon App Store) called iTracx, which allows you to glance at today’s lowest... Read more
Apple price trackers, updated continuously
Scan our Apple Price Trackers for the latest information on sales, bundles, and availability on systems from Apple’s authorized internet/catalog resellers. We update the trackers continuously: - 15″... Read more
Apple refurbished 2016 13-inch MacBook Airs a...
Apple has Certified Refurbished 2016 13″ MacBook Airs available starting at $849. An Apple one-year warranty is included with each MacBook, and shipping is free: - 2016 13″ 1.6GHz/8GB/128GB MacBook... Read more
1.4GHz Mac mini on sale for $449, save $50
Adorama has the 1.4GHz Mac mini on sale for $50 off MSRP including free shipping plus NY & NJ sales tax only: - 1.4GHz Mac mini (Apple sku# MGEM2LL/A): $449 $50 off MSRP To purchase a mini at... Read more
Apple refurbished 2015 13-inch MacBook Airs a...
Apple has Certified Refurbished 2015 13″ MacBook Airs available starting at $759. An Apple one-year warranty is included with each MacBook, and shipping is free: - 2015 13″ 1.6GHz/4GB/128GB MacBook... Read more

Jobs Board

*Apple* Retail - Multiple Positions- Akron,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Hardware Design Validation Engineer - *Apple...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more Read more
Systems Architecture Prototyping - *Apple*...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more Read more
*Apple* Retail - Multiple Positions- South B...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.