TweetFollow Us on Twitter

I Heart vi

Volume Number: 22 (2006)
Issue Number: 12
Column Tag: Mac in the Shell

I Heart vi

Text editing in a shell

by Edward Marczak

Introduction

It's amazing that a basic function like text editing can be so...obtuse. vi and emacs have confounded new users since they arrived on the scene. However, editing text is such an important part of any Unix or Unix—like system, that I'd be remiss if I didn't address it. This month, I'll cover basic vi — enough to make you comfortable the next time you've ssh—ed into a remote machine and need to edit a file.

Growing Up

Practically each month, this column asks you to type something into a text editor. Of course, this can be TextWrangler, SubEthaEdit or even Dreamweaver or the XCode IDE. But if you already have a shell open, or, only have the option of a shell, then an editor like vi, emacs or pico are your best options. I'm well aware of the vi/emacs debates. Emacs is truly a Swiss Army Knife of an application. Perhaps I'll cover it someday. However, for some reason, I just dug into vi more, and have stuck with it; Turns out to have been a useful choice. If you've ever needed to alter privileges for sudo users, you'll note that the 'right' way to edit the sudoers file is by using visudo — basically, a stripped down version of vi. On other Unix systems, there's typically a vipw and vigroup app. All three, by default, use vi as the editor. Also, ever notice which editor you use when editing crontabs with crontab —e? So, vi is very good to know — at least the basics.

Quick little secret before we start: traditional vi is pretty much gone, and has been supplanted with vim, VI Improved. You'll note that vi is simply a link to vim:

$ ls —ld /usr/bin/vi*
lrwxr—xr—x	1	root wheel	3	Jan	18 2006 /usr/bin/vi —> vim
lrwxr—xr—x	1	root wheel	3	Jan	18 2006 /usr/bin/view —> vim
—rwxr—xr—x	1	root wheel	2060380 	Dec	25 2005 /usr/bin/vim
lrwxr—xr—x	1	root wheel	3	Jan	18 2006 /usr/bin/vimdiff —> vim
—rwxr—xr—x	1	root wheel	1068 	Dec	25 2005 /usr/bin/vimtutor
—r—xr—xr—x	1	root wheel	34472 	Dec	25 2005 /usr/bin/vis

OS X v10.4 ships with vim v6.2. You can download the latest — version 7 — and compile it up, as it compiles and runs cleanly under OS X. However, there's no need to do that to follow this particular column.

The Tower That Ate People

If you've never used vi, we'll take it step—by—step. So, open up your favorite terminal app and get a shell. You may as well stay in your home directory, as we're not going to make too much of a mess.

To start the editor, simply type vi, and you'll be greeted with a startup screen. Unlike Word or Pages, you can't simply start typing. Well, you can, but each keystroke may not do what you expect. Those of us that go back to Mac OS 9 will remember modal dialogs. Basically, a modal dialog box stopped you from using anything else until you acknowledged it. You were put in the mode of having to deal with whatever message it presented. vi is a modal editor. You'll either be in one of three modes: normal mode, 'edit' mode, or ex command mode. What you're looking at now is normal mode: vi awaits your instruction.

Press i. Now, I should tell you here that commands in vi are case sensitive. Typically, the lowercase version means one thing, and the uppercase/shifted version negates, or is the opposite of the lower case (or, non—shift) version — this makes commands a little easier to remember. So, you've pressed i, and you now see "— INSERT —" at the bottom of the window. Great! Your first vi command. No sweat, right? Now you're in insert mode. This is pretty much what you expect. Go ahead, type. How about we all type the same thing. We'll start out easy; try this, pressing return at the end of each line, mistakes and all:

trust a few people
love all
do wrong to none

Not too terrible, right? Pressing the escape key on your keyboard will put you back in normal mode. The "— INSERT —" should disappear.

Now, I didn't get the quote quite right. Let's fix it. Apple has nicely mapped most keys sanely; they do what you expect. This includes the arrow keys. However, this may not be the case on all systems, so, if you'd like to get used to the vim way, I'll show you now. This will also help your Nethack skills (http://www.nethack.org). k is cursor up, j is cursor down, while h moves the cursor left, and l moves it right. Perhaps not the easiest to remember. Different people have different ways to remember this, but, I simply suggest a Post—it note and some practice. Why these keys? Vim and vi strive to be efficient editors. I love to use vi as I never have to take my hands off of the keyboard, nor stray too far from the home row. That's efficiency. If you're 100% Mac—dedicated, though, the arrow keys will suit you just fine, too. Digression aside, please move the cursor to the first character, the 't' in 'trust'.

Well, if that's the beginning of a sentence, it should be uppercase. There's two ways to tackle this, and we'll start with the easier of the two. With the cursor on the 't', press ~ (tilde). This toggles the character under the cursor between upper and lower—case, and then advances the cursor. Ah, but wait, that's not the correct beginning of that quote! With your cursor on that line, type dd, which will delete the line and place it in the yank buffer. Now, press p which pastes the contents of the yank buffer on the line following.

Now, our capital letter leads the second sentence, which naturally isn't right. Twiddle it back using the tilde key (~). Cursor up and onto the 'l' in 'love', and we'll replace it with an uppercase version — this time, though we'll do just that: replace. Type r, followed by 'L'. r will replace one character. So, when you typed the 'L', you simply replaced what was there. Time for the correct punctuation.

With the cursor still on the first line, type A, for 'append to end of line' (make sure it's capital A!). Your cursor will jump to the end of the line and you'll enter insert mode — look for the "— INSERT —" message in the status line. Type a comma, and press escape to get back into normal mode.

Cursor down to the second line, and then right to the 'p' in 'people'. Delete, one character at a time using the x command, the word 'people', but leave the space after 'few'. Replace the space with a comma, using r, followed by a comma. At this point, you should have:

Love all, 
trust a few,
do wrong to none

...with your cursor on the comma after 'few'. Cursor down to the third line and type $ — jump to the end of the current line. Press a (the letter 'a') — append after the cursor — and type a '.' (period). (Those of you paying attention will realize that this could have been done in one step with capital A...but how else was I to stick in the $ command to jump to the end of a line?) Press escape to go back to normal mode.

Cursor up to the first line and press J (capital J). This will join this line with the one following. Do it again, and you'll end up with one single line:

Love all, trust a few, do wrong to none.

And Through The Wire

So, now you have the very basics of editing with vi. I mentioned that vi begat vim, but I didn't yet tell you that ex begat vi. The foundation of certain commands are ex commands. You enter ex command mode, by typing a colon (":"). You'll see a colon appear on the status line, and the cursor will jump down to immediately follow it. Type w ws.txt. 'w' is for 'write', and will write the file 'ws.txt'.

If you need to take a break, you can type :q to quit. Re—enter vi while loading the file like this: vi ws.txt.

We've looked at three ways to get into insert mode so far: 'i', for insert in place, 'a' for append at the cursor and 'A', which appends at the end of the current line. Here's one more: o. This opens a new line beneath the current line. Try it now.

Don't forget! vi inherits all of the integration that using Terminal.app brings OS X users. The best is drag—and—drop. While in insert mode, you can pick up a text or .clipping file and drop it on the terminal. The contents will insert at the cursor.


Figure 1: Dragging a .clipping file to Terminal.app while editing in vi

Try it now, while you're still in insert mode!

At this point, I encourage you to quit vi — :q — and type vimtutor. It's an interactive vi tutorial that takes about 15—20 minutes. Good, basic practice and tips.

More Than This

vimtutor does a good job of covering the basics. Let me wrap up with some of my favorites that neither I or vimtutor have introduced you to.

:shell — this ex command lets you escape to a shell, do your work, and then when you exit, you'll find yourself right where you left off. Now, certainly, this function has lost some value in the days of multi—window machines, but sometimes, it's really handy. It let's you get a lay of the land, and then pick up right from where you left off.

vimtutor shows you how to run an external shell command, but at times, there's even something more useful: running a command and inserting its output at the cursor. To preface this, you can read in a file using the r ex command. You can even read in the file you're working on. Try it now with :r ws.txt. You'll see the contents of the file — as it is on disk — appear inserted into your file after your cursor. Similarly, you can read in the output of a shell command with r !. Insert all of the users from Directory Services into your file with:

:r !dscl localhost list /Search/Users

This comes in very handy. Instead of running a command, redirecting output to a file and then editing that file, you can do it in one step in vi.

vimtutor also shows you how to search using the / normal command. If you didn't run through vimtutor, do it now. Really. Here's two things they didn't get into fully. Load up vimtutor, as it provides ample text for us (quit your current session with :q, and then type vimtutor at the shell prompt). Put the cursor on the first occurrence of the word "commands". You should see several of them. Press * (asterisk). vi automatically starts searching on that word, and jumps to the next occurrence. You can jump between occurrences with n and N. n jumping to the next (forward) occurrence, and N jumping backward.

Anyone familiar with sed will feel right at home with vim's search and replace function. vimtutor showed you searching with /. Search and replace is accomplished with :% s/old/new/g. The "%" represents the entire file. Without it, you're only searching the current line. Additionally the "/g" means global, and without that flag, only the first occurrence on each line would be replaced. You can also use the c flag to have vi ask for a confirmation. Go to the top of the file and try this:

:% s/commands/friends/gc

All occurrences of "commands" will be changed to "friends" and you'll be asked for confirmation of each change. You may notice that this substitution works surprisingly well!

Finally, one option I use quite often: changing line endings. Since a file is just a stream of bytes, the computer needs some way to recognize when humans want to see a new line. Unfortunately, the three major platforms all decided on different ways. Unix and Unix—like systems use a line—feed character (LF), ascii 0x0A. DOS uses both a new line (NL, or carriage return CR) and line feed. When DOS sees CRLF, ascii 0x0D 0x0A, it knows to show us humans a new line. Finally, Mac systems traditionally have used a new line only. The current state of line endings under OS X is a bit of a mish—mash. Most GUI apps still use CR, where most (if not all) shell apps use LF.

Many times, you'll receive a DOS line—ending—formatted file that should have Unix line endings. vi handles this with aplomb. Use :set ff=unix and then write the file with :w. Done! Go the other way with :set ff=dos. Sometimes this shows up as ^M (ctrl—M) characters — that's the extra CR character. Just change the file type and write it out.

Don't Give Up

vi is a craftsman's tool. Like any tool, it requires a little work and practice to learn in depth, or to make second nature. I hope next time that you're into a remote system and need to edit a file, or for some reason are forced to use vi, that you'll be confident in your usage. In the spirit of self exploration, take a look at all of the settings that can be changed to tailor vi to your style by trying :set all.

Be aware that there is a GUI version of vim available at <http://www.macvim.org>. It may not be a GUI app the way you think of one, but it is integrated with the Aqua environment. Frankly, though, I never really saw the point in X11 or GUI versions of vi or emacs. In those environments, you'll have access to a shell, so why not use it as intended?

Media of the month: Up, by Peter Gabriel. A masterpiece. Seriously. If, for some reason, that doesn't do it for you, just take some time to put on some headphones (real cans, not those iPod things), lay down, and really listen to some music.

See everyone next month at MacWorld, I hope! I'm presenting two sessions, and will be hanging around the MacTech booth, so please make sure you stop by and say hello!

References

The vi man page

Vim home: http://www.wim.org

Nethack: http://www.nethack.org

"All's Well That Ends Well," William Shakespeare


Ed Marczak owns and operates Radiotope, a technology consulting practice with a focus on business process enhancement, network and system integration, and, more generally, all things Mac.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Bookends 12.8 - Reference management and...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Bookends uses the cloud to sync reference libraries on all the Macs you use.... Read more
Apple iTunes 12.6 - Play Apple Music and...
Apple iTunes lets you organize and stream Apple Music, download and watch video and listen to Podcasts. It can automatically download new music, app, and book purchases across all your devices and... Read more
Default Folder X 5.1.4 - 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
Amazon Chime 4.1.5587 - Amazon-based com...
Amazon Chime is a communications service that transforms online meetings with a secure, easy-to-use application that you can trust. Amazon Chime works seamlessly across your devices so that you can... Read more
CrossOver 16.2 - Run Windows apps on you...
CrossOver can get your Windows productivity applications and PC games up and running on your Mac quickly and easily. CrossOver runs the Windows software that you need on Mac at home, in the office,... Read more
Adobe Creative Cloud 4.0.0.185 - Access...
Adobe Creative Cloud costs $19.99/month for a single app, or $49.99/month for the entire suite. Introducing Adobe Creative Cloud desktop applications, including Adobe Photoshop CC and Illustrator CC... Read more
MegaSeg 6.0.2 - Professional DJ and radi...
MegaSeg is a complete solution for pro audio/video DJ mixing, radio automation, and music scheduling with rock-solid performance and an easy-to-use design. Mix with visual waveforms and Magic... Read more
Bookends 12.8 - Reference management and...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Bookends uses the cloud to sync reference libraries on all the Macs you use.... Read more
Adobe Creative Cloud 4.0.0.185 - Access...
Adobe Creative Cloud costs $19.99/month for a single app, or $49.99/month for the entire suite. Introducing Adobe Creative Cloud desktop applications, including Adobe Photoshop CC and Illustrator CC... Read more
Default Folder X 5.1.4 - 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

The best deals on the App Store this wee...
Deals, deals, deals. We're all about a good bargain here on 148Apps, and luckily this was another fine week in App Store discounts. There's a big board game sale happening right now, and a few fine indies are still discounted through the weekend.... | Read more »
The best new games we played this week
It's been quite the week, but now that all of that business is out of the way, it's time to hunker down with some of the excellent games that were released over the past few days. There's a fair few to help you relax in your down time or if you're... | Read more »
Orphan Black: The Game (Games)
Orphan Black: The Game 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Dive into a dark and twisted puzzle-adventure that retells the pivotal events of Orphan Black. | Read more »
The Elder Scrolls: Legends is now availa...
| Read more »
Ticket to Earth beginner's guide: H...
Robot Circus launched Ticket to Earth as part of the App Store's indie games event last week. If you're not quite digging the space operatics Mass Effect: Andromeda is serving up, you'll be pleased to know that there's a surprising alternative on... | Read more »
Leap to victory in Nexx Studios new plat...
You’re always a hop, skip, and a jump away from a fiery death in Temple Jump, a new platformer-cum-endless runner from Nexx Studio. It’s out now on both iOS and Android if you’re an adventurer seeking treasure in a crumbling, pixel-laden temple. | Read more »
Failbetter Games details changes coming...
Sunless Sea, Failbetter Games' dark and gloomy sea explorer, sets sail for the iPad tomorrow. Ahead of the game's launch, Failbetter took to Twitter to discuss what will be different in the mobile version of the game. Many of the changes make... | Read more »
Splish, splash! The Pokémon GO Water Fes...
Niantic is back with a new festival for dedicated Pokémon GO collectors. The Water Festival officially kicks off today at 1 P.M. PDT and runs through March 29. Magikarp, Squirtle, Totodile, and their assorted evolved forms will be appearing at... | Read more »
Death Road to Canada (Games)
Death Road to Canada 1.0 Device: iOS Universal Category: Games Price: $7.99, Version: 1.0 (iTunes) Description: Get it now at the low launch price! Price will go up a dollar every major update. Update news at the bottom of this... | Read more »
Bean's Quest Beginner's Guide:...
Bean's Quest is a new take on both the classic platformer and the endless runner, and it's free on the App Store for the time being. Instead of running constantly, you can't stop jumping. That adds a surprising new level of challenge to the game... | Read more »

Price Scanner via MacPrices.net

2.6GHz Mac mini on sale for $559, $140 off MS...
Guitar Center has the 2.6GHz Mac mini (MGEN2LL/A) on sale for $559 including free shipping. Their price is $140 off MSRP, and it’s the lowest price available for this model. Read more
SSD Speeder RAM Disk SSD Life Extender App Fo...
Fehraltorf, Switzerland based B-Eng has announced they are making their SSD Speeder app for macOS publicly available for purchase on their website. SSD Speeder is a RAM disk utility that prevents... Read more
iPhone Scores Highest Overall in Smartphone D...
Customer satisfaction is much higher among smartphone owners who use their device to operate other connected home services such as smart thermostats and smart appliances, according to the J.D. Power... Read more
Swipe CRM Free Photo-Centric CRM Sales DEal C...
Swipe CRM LLC has introduced Swipe CRM: Visual Sales 1.0 for iPad, an app for creating, managing, and sharing visually stunning sales deals. Swipe CRM is targeted to small-and-medium creative... Read more
13-inch 2.0GHz Apple MacBook Pros on sale for...
B&H has the non-Touch Bar 13″ 2.0GHz MacBook Pros in stock today and on sale for $150 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.0GHz MacBook Pro Space Gray (... Read more
15-inch Touch Bar MacBook Pros on sale for up...
B&H Photo has the new 2016 15″ Apple Touch Bar MacBook Pros in stock today and on sale for up to $150 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.7GHz Touch Bar... Read more
Apple’s iPhone 6s Tops Best-Selling Smartphon...
In terms of shipments, the iPhone 6s from Apple bested all competitors for sales in 2016, according to new analysis from IHS Markit, a world leader in critical information, analytics and solutions.... Read more
Logitech Rugged Combo Protective iPad Case an...
Logitech has announced its Logitech Rugged Combo, Logitech Rugged Case, and Logitech Add-on Keyboard for Rugged Case for Apple’s new, more affordable $329 9.7-inch iPad, a complete solution designed... Read more
T-Mobile To Offer iPhone 7 and iPhone 7 Plus...
T-Mobile has announced it will offer iPhone 7 and iPhone 7 Plus (PRODUCT)RED Special Edition in a vibrant red aluminum finish. The introduction of this special edition iPhone celebrates Apple’s 10... Read more
9-inch 128GB iPad Pros on sale for $50-$70 of...
B&H Photo has 9.7″ 128GB Apple WiFi iPad Pros on sale for up to $70 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 9″ Space Gray 128GB WiFi iPad Pro: $649 $50... Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Fulltime aan de slag als shopmanager in een h...
Ben jij helemaal gek van Apple -producten en vind je het helemaal super om fulltime shopmanager te zijn in een jonge en hippe elektronicazaak? Wil jij werken in Read more
Starte Dein Karriere-Abenteuer in den Hauptst...
…mehrsprachigen Teams betreust Du Kunden von bekannten globale Marken wie Apple , Mercedes, Facebook, Expedia, und vielen anderen! Funktion Du wolltest schon Read more
*Apple* Retail - Multiple Positions- Chicago...
SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Fulltime aan de slag als shopmanager in een h...
Ben jij helemaal gek van Apple -producten en vind je het helemaal super om fulltime shopmanager te zijn in een jonge en hippe elektronicazaak? Wil jij werken in Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.