TweetFollow Us on Twitter

The Terminal: Why?

Volume Number: 21 (2005)
Issue Number: 2
Column Tag: Programing

Mac In The Shell

by Edward Marczak

The Terminal: Why?

Love it or leave it!

You've got a fancy Aqua GUI in front of you (errr...if you have the print magazine in front of you, look at your OS X box now), why would anyone use the command line? The command line!?! We're here at MacTech because we use a Mac - the computer that popularized the GUI!!! The computer that said, "CLI? Gag me with a spoon!" (well, it was California in the 80's). However, despite Apple initially eschewing a command line altogether, the CLI has survived. There's a lot of power there, and OS X lets you tap into it. Furthermore, anyone can fire up a GUI utility and make some changes. But if you want to impress your date, you have to learn some command line tricks.

If you're a bit more of a CLI veteran, but are coming from a different platform, you may simply want to jump down to 'Apple-fying the CLI".

The Past

I work with a broad spectrum of people that reign over technology in some way: from low-level hardware and software hackers, to networking experts, high-level FileMaker developers and GUI-rangers. These people have all learned, or come close to mastering, the command line, and are better for it. I've grown up in a world of teletypes, Commodores, IBMs, Unix boxes, Apples, Netware servers, DOS and Windows environments. All of these machines started with a command line (and some ended there). In the timeline of computing, the GUI was an afterthought. Not for the Mac, of course. But go back to an Apple II, (if you've got one laying around!) and you'll find that when you boot up, you're presented with a ']' prompt and blinking cursor. Since this environment has been around so long in the Unix world, it is very well thought out and very mature. But it's certainly one of the reasons people not-in-the-know would panic when they'd turn on a computer. What do I do? It's just sitting there blinking at me. Will I break it if I type the wrong thing?

The Mac OS tried to end all of that command line fear and present a graphical interface at boot time that made people feel comfortable. They did a great job. But fast-forward to now, and Apple is singing a slightly different tune. However, I find many people who are dyed-in-the-wool Mac users simply pretend that doesn't exist.

The Present

Here we are, and there's a command line in a Macintosh operating system. They just couldn't keep it out of there. In all honesty, if it weren't in there, I'd be writing for a Linux magazine right now. As a techie, and someone who likes (and many times needs) to troubleshoot, there was no bigger breath of fresh air when I fired up under OS X (10.0 beta, on my Powerbook G3). I immediately typed 'ping' for the network I was on and saw the replies come back. Wow, Apple did it. Keep Word. Keep Safari. Heck, even keep Quake and Tron 2.0, I don't want a computer without access to the command line. But why?

Terminally Acquainted

I mentioned the power that lies in the terminal, what is that all about? Why is it so much more powerful? Firstly, you can typically type more quickly than you can mouse around. From time to time, I see people launch Calculator and click on each number rather than use the number pad on their keyboard. Doing that just doubles the time required. Secondly, as people like to customize their GUI (I'll admit that when I work on other people's machines and I find the dock on the left it drives me a bit batty...) and GUIs change over time (look at the differences going from 10.0 to 10.3), the CLI is pretty much the CLI. Of course, it can be customized, but it's usually done in such a way that it doesn't change the way standard utilities run. Third, it gives you a consistent way to administrate a machine. Fourth, it gets you a little closer to the operations of the machine. Have you ever had the GUI lock up on you? I have. But everything else was still running and I was able to console in and reset the machine gracefully. Fourth, and most importantly, Apple lied to us! When OS X shipped, we were told that we'd never have to see a command prompt if we didn't want to. OK, perhaps not. But that stopped us from doing certain things with our machines. While the entire situation is getting better, there are things you can do in the terminal that there is simply no GUI equivalent for. With those notes, let's get familiar with Apple's, starting with the configuration that ships with OS X 10.3.

Launch from /Applications/Utilities/Terminal. Perhaps the fact that you find the app in 'Utilities' rather than 'Applications' is something that scares people right away, as if it's not something one should normally run. Figure 1 shows approximately what the default terminal looks like.

Figure 1 - A default terminal in OS X (Panther 10.3.7)

I say 'approximately' because you will have some differences. Of course, the time of your last login will be different. Unless you've already changed it, your "message of the day" will still read "Welcome to Darwin!" The next line is your prompt, and it is generated at run-time. 'Jack-Kerouak' is the name of my machine (because, if you must know, it's a laptop and I'm always "On the Road"), and you'll have the host name of your machine. The "~" shows my current path, and by default, we start out in our home directory (which is represented by the tilde). "game" is the short name of the account I'm logged in as (remember: Quake and Tron 2.0!), and you'll have your user name. Then, there it is, the cursor. Patiently waiting for you to type.

Black text on opaque white. Boring. Lets go check our window settings. Choosing the "Terminal->Window Settings..." menu gives us some ways to modify the look and behavior of the terminal. Figure 2 shows the first of several preferences that can be changed in the 'Terminal Inspector'.

Figure 2 - Terminal Window Settings

Of course, these are all preferences, and are unique to each individual. I'm going to share how I like my terminal to behave, but by all means, choose what makes you most comfortable.

The first set of preferences, "shell", gives us one option: choose what to do when the shell is done. I think I've only had one occasion to keep it at the default, so I immediately change this to "Close only if the shell exited cleanly."

The "process" preferences work perfectly at "prompt before closing window if there are processes other than:". I like being prompted as little as possible for anything. The "emulation" settings have good defaults, but may need to be tweaked for a particular case. The only thing I do here is check the "option click to position cursor" checkbox, despite actually using that function very little myself.

The "buffer" preferences only deserve one change: set the scrollback to 'unlimited'. If you ever start compiling things from the command line, like a custom Apache install, 10,000 lines can disappear pretty quickly.

The "display" preferences are a little more fun, as their effects can be seen instantly. See figure 3 to get a look at this one.

Figure 3 - Display settings

Call me old-school, but I want a block cursor that blinks. Depending on the display I'm using, I'll sometimes drop the point size down to 9. A quick tip for you: never turn on anti-aliasing. Not only does it look terrible, it slows down - yes, even more so than it starts out. This is one valid gripe that users of have. Its speed is nowhere near a real terminal, a terminal emulator on other systems, or even a Windows DOS box (or, for that matter 'DOSbox' under OS X. Man is that thing quick!). While things did get better in Panther, Terminal is still the laggard, comparatively. But, hey, it looks great.

Next up are the color prefs, which go hand in hand with the display prefs. Have fun with this one: there are no wrong answers here. Come up with a style that is easy on your eyes and makes you feel at home. Again, I go for the old-school combo of green on black, with a pinch of ultra-modern transparency. I have one terminal combo of light-blue on dark-blue with a rather large font. Yes, it looks like a Commodore 64....

Stepping down brings us to the 'Window' preferences. I tend to check off just about everything in the lower-half of the inspector window. Additionally, I like to make the terminal fairly large. Why have text wrap if it doesn't have to?

On the last page of options, the 'keyboard' prefs allow one to alter the escape codes that are sent to for each key. Unless you have a great need to change these (and you may), just leave these at their default settings.

Now, I know you've been eyeing that large "Use Settings as Defaults" button at the bottom of the Inspector window. Well, if you have everything set the way you like, click it! As soon as you click it....nothing happens! Well, OK, it does save your preferences, but there is absolutely no feedback that it done anything. For proof, quit and relaunch it. You should now have a terminal that defaults to your settings. Nice, eh?

Now What?

So, now we've made the terminal pretty. Great. Besides staring at a blinking cursor, now what? Let's start with the basics. Again, you'll see where you are in the filesystem based on your prompt, which at first should read '~'. We can start from the top to best illustrate how this works. The very top level of the filesystem is represented by '/', or, 'the root'. Type 'cd /' and press enter. This will 'c'hange 'd'irectory to "/". You're now at the top level of your disk tree, basically represented by "Computer" in the Finder. You should also notice that the terminal prompt changed from "~" to "/". Now, type "cd Users" (capitalization is important). You've moved into the familiar Users folder. Let's see what's in here. Type "ls -l". This produces a file 'l'i's'ting of the current directory. The '-l' following the command is a switch that modifies the behavior of the command. In this case, we want a 'l'ong list. Try an 'ls' without the '-l' switch and you'll immediately see the difference (and, hopefully, why I prefer the long list).

So far so good, right? Nothing broke. Just remember, although the terminal brings you down to a lower level, there's still a thin veneer between you and the OS. Not quite the movie screen the GUI covers everything up with, but still, a level of abstraction exists. For example, when you ask for a file listing by typing 'ls', sure, you had to do something manually. Directory information didn't just come flying onto your screen. But neither did you have to tell the disk drive which blocks to access. So, as always, unless you pour liquid onto your CPU, you're not going to break anything.

If you feel comfortable with these two basic exercises, the command line just may be for you! Naturally, this doesn't scratch the surface of what can be done via the CLI. Not even the surface of the smallest surface that exists on the surface of the CLI.

Want More?

Listing files? I can do that in the Finder! Where's the power? If you're comfortable moving from directory to directory, we can look at some more powerful commands.

Continuing with file related commands is important, as Unix treats just about everything as a file. Your disk drive? A file. Even the terminal display can be treated as a file. We'll get into this deeper in future columns, but safe to say, file manipulation is important.

Back in the terminal, type 'cd'. Simply typed by itself, the change directory command will bring you back to your home directory. Now, type 'touch thefile.txt'. In short, the touch command will either create a zero-length file, or, if the name you specify already exists, will update the date stamp of that file to the current date and time. Get a directory listing and see if your file is there ('ls -l', remember?).

To copy that file, you use the 'cp' command. Type 'cp thefile.txt theotherfile.txt'. 5 points if you typed 'cp thef' and hit tab to complete. This will copy 'thefile.txt' to a file called 'theotherfile.txt'. We can alter these files as well as having copied them. There are some holy wars in Unix-land as to the best text editor in the world. I use vi. No apologies, that's just what I use. It will absolutely be the subject of a future column. If you know another text editor, feel free to use it here.

Invoke vi (the 'v'isual 'e'ditor) by typing 'vi theotherfile.txt' (did you use tab completion?). You'll be presented with a blank-ish looking screen with tildes running down the left-hand side. Figure 4 should mirror what you're seeing.

Figure 4 - vi with an empty file

The tildes represent a non-existent line, which, admittedly, can sometimes get confusing if you're editing a file with tildes. I'll just give the key presses with a short description, since I'll cover vi in a future column - case is important, by the way. Press 'i' for 'i'nsert - you're now free to roam about the cabin. You should see a bold 'INSERT' notification at the bottom of the edit window. Type whatever text you'd like. I just typed 'This is a test.' When you're done, press the escape key on your keyboard. Type ":" (colon), and you should see a ":" appear at the bottom of the window you're editing in. Follow that with 'wq' and press Enter. That tells vi to 'w'rite the file to disk and then 'q'uit. You'll be dropped back to your prompt.

I'd like to delete the original file that we created. This is done with the 'rm' command. Now, just like files that you throw in the Trash via the Finder, be careful what you follow the 'rm' command with. Unlike the trash, though, the files that you list will be deleted immediately. No trash, no undo. Gone. Tab completion can be great, or you can use it without thinking after an rm command and nuke the wrong file. Be careful out there! That said, type 'rm thefile.txt' and, after checking yourself, press Enter. You've just deleted 'thefile.txt'.

The 'mv' (move) command moves and renames files. Renaming, after all, is just moving a file within the same directory. Type 'mv theotherfile.txt thelastfile.txt' and press Enter. 'theotherfile.txt' just became 'thelastfile.txt'.

To bring this all home, we can open the file we created in the Finder. Switch to the finder, and open your home directory. 10 points if you've left a Finder window of your home directory open this whole time and watched all of these machinations take place. You should see a text file named 'thelastfile.txt' sitting there. If you double click it, it should simply launch TextEdit. Check out our handiwork in Figure 5.

Figure 5 - TextEdit displaying our file

While this was all a bit contrived and trivial, I'm sure you can imagine some automated routines that compile information, save it to a file, and then display it via TextEdit or any other program. In fact, let's try something a little more serious.

Hop back over to terminal. Fire up vi or your favorite editor. I'll give instructions for vi. Type 'cd' so you're sure you are in your home directory. Type 'vi'. This will be a bash script that will show us a report of disk information for our main disk and display it in TextEdit. Press 'i', and you'll again see the bold 'INSERT' along the bottom of your editor window. Type the following exactly:

#!/bin/bash diskutil info /dev/disk0 > 
/tmp/disklist.txt open 

Save this file by pressing escape, typing ':wq' and pressing Enter. Type 'chmod 700' and press enter. This gives this script the ability to be executed (run) as a program (ok, this is a bit simplified, but without this command, this script is just a text file).

Before we run this, let me note that you'll need to be an admin for this to work. When you're ready, type "./" to run our script. That's dot, forward-slash, Don't forget the tab-completion for this one! Press enter. In about two seconds, TextEdit will pop up with a short report about our disk 'disk0'. See figure 6 for what this looks like.

Figure 6 - Our script in action.

Again, the details of this script and all the commands we typed will be covered in future articles.

Apple-Fying The CLI

If you're a more seasoned user, you may have skipped some of the earlier bits of this article. You already know your way around. You know what a hard link is and you know how to use it. You like to fire up, dive in and never look back. Some things that may escape you if you're coming from another environment:

If you're a big xterm person, there are some notable differences here. Mainly:

  • doesn't honor switches (like "-bg") that allow you to customize the Terminal at app launch. You have to use Terminal Inspector as described earlier.
  • $TERM defaults to "xterm-color", which is great on your own system, but can throw remote systems not ready for it.
  • You can't launch a new terminal from the command line! Goofy, eh? You just have to slap Apple-N.

However, despair not. There are some really nice Terminal attributes. Such as:

  • You can set your window title on the fly (though escape sequences and an 'echo').
  • Split-screen bar (see figure 4)
  • Tab completion. I couldn't survive without tab completion.
  • Integration with the Services menu.

We'll step through these bits here.

If you're really into customization and want to set your window title from the command line, or have a script that uses this functionality, you can! Try this:

echo -n -e "\033]0;Title\007"

The "\033" is the 'escape' key, needed to start an ANSI escape sequence. Follow this code with the title you want, and close it out with a "\007".

You can split your terminal horizontally by clicking the 'broken square' icon in the upper right-hand corner of the terminal window. This will display a horizontal bar that can be adjusted to size the windows as needed. Figure 4 shows a split screen with a file listing in the upper split, and 'top' running in the lower pane. While this functionality is useful, I use it very little. The reason for that will be part of a future article.

Figure 7 - Terminal with split-screen activated

Tab completion!!! All Unix veterans know some kind of completion. And when you start using it, you'll never give it up. For you hard-core Unix people: OS X has standard tab-completion, 'nuff said. If you don't know what this is, here's an illustration: once again, type 'cd /' to get to the root. Now, type 'cd Li' and then press the 'tab' key. Suddenly, the line you're working on fills itself out (to become 'cd Library/'). Now, type 'W' and a 'tab'...boom! You now have 'cd Library/WebServer'. This cuts down on the keystrokes you need to type by a huge factor. Sometimes, your hit 'tab' and you simply hear a beep. That's either because nothing matches, or more than one thing matches. As an example, if you still have Classic loaded on your machine, and you type 'cd /Sy' and press tab, you get a partial completion (to 'System') and a beep. If you press 'tab' again, the shell will show you the matches. In this particular case, you can either accept the match of 'System' (because it's valid), or type '\ " (backslash-space) and press 'tab' again to have the shell complete the next match. The more you use it, the more you'll get the hang of it. Just don't practice on Windows XP, which now supports tab completion, but has a really poor substitute of it.

OS X has a great feature in the Services Menu - which someone else can cover much better than I can. has nice integration with this menu. Highlight some text, and then go check Terminal->Services. There's some nice functionality there, such as: Send to mail, create new sticky note, create new window in TextEdit, and more.

One last note for those so inclined: You should also take a look at the actual Terminal preferences, accessed through the 'Terminal->Preferences' window. This will allow you to define several aspects about your terminal that can help out in situations where you're trying to emulate a different terminal. Be aware that changing the shell in the Terminal preferences screen will only change it for shells launched through Alternate terminals (see below) and ttys from remote sessions, such as telnet or ssh, use the shell defined in your user profile. The good old 'chsh' works for this purpose, or, if you want to get all OS X about it, change the shell key in your NetInfo record.

The Future

Well, naturally, I can't predict the future. But I can tell you that a text, command line interface will be with us for some time to come. There are new applications showing up all the time that are CLI only. You can find MP3 players, Gnutella clients, games, web browsers, e-mail programs and more, that are all CLI driven. Although the Mac certainly needs it less than other platforms, which may still be text-driven by nature, learning the CLI is of great benefit. It helps you troubleshoot a Mac with a boot time problem, and it can help you automate your machine in better circumstances.

I'd be remiss if I didn't mention that Apple's isn't the only terminal for OS X! There are two more that I'm aware of. GLTerm takes the speed issue head on. All display is done through OpenGL. It also supports X .bdf fonts. There may be cases where doesn't handle some graphics issue correctly. Chances are, GLTerm will handle those cases just fine. Find it at

The second terminal alternative is iTerm. iTerm shoots for features. If you spend time in KDE or Gnome, check out iTerm. It has support for bookmarks (saving session settings), tabs, an anti-idle function and more. You can find it at

The End

This is the end...of this column only (whew!) Obviously, I'm a huge proponent of the CLI. Now, I'm not so stubborn that I use the Terminal for everything! After all, I am a Mac user!


Anyone who read my 'Unix in OS X' article that appeared in the December MacTech should note that I did find the solution to making an OS X 10.3.4 through 10.3.7 machine accept remote syslog connections. In your /etc/rc file, you need to alter the syslog invocation to read:

/usr/sbin/syslogd -a\* -m 0

where the IP address and mask (in CIDR notation) represent the interface to listen on.

Unfortunately, this incantation has changed a few times and the syslog binary is out of sync with the man page. Stay tuned for any changes to remote logging!"

When he's not helping the clients of Radiotope, you'll find Ed Marczak on the grid, fighting for the users.


Community Search:
MacTech Search:

Software Updates via MacUpdate

The best scanner app on mobile
People always say that the best camera is the one you have with you. Well, the same is true with scanners, and your phone can be a pretty great tool for scanning receipts and other documents while you're on the go. [Read more] | Read more »
MARVEL Avengers Academy guide - How to g...
MARVEL Avengers Academy lets you build your own superhero school and fill it with heroes from the Marvel universe. It can be a little slow going to get your school's attendance up though, so we've gathered together somesome tips to help you do this... | Read more »
Shadow Blade: Reload guide - How to hack...
Shadow Blade: Reload is the kind of action-platformer that would have happily sucked up hours of your time on a console a few years back.Now, you can take it with you wherever you go, and its mobile conversion is not too shabby at all. To help you... | Read more »
Tomb of the Mask guide - How to increase...
Tomb of the Mask is a great endless arcade game from Happymagenta in which quick reflexes and a persistent attitude can go a long way toward earning a top score. Check out these tips to see if you can give yourself an edge on the leaderboards. [... | Read more »
Smooth Operator! (Games)
Smooth Operator! 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Smooth Operator is a weird, weird two-player kissing game. Squeeze in for 2 player fun on a single iPad, creating awkward... | Read more »
Sinless: Remastered (Games)
Sinless: Remastered 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: | Read more »
_PRISM Guide - How to solve those puzzle...
_PRISM is a rather delightful puzzle game that’s been tailor made for touch screens. While part of the fun is figuring things out as you go along, we thought we’d offer you a helping hand at getting in the right mindset. Don’t worry about messing... | Read more »
Fractal Space (Games)
Fractal Space 1.3.1 Device: iOS Universal Category: Games Price: $.99, Version: 1.3.1 (iTunes) Description: Live the memorable experience of Fractal Space, a unique first person adventure & puzzle game by Haze Games! Will you... | Read more »
Set off on an adventure through the Cand...
Like match three puzzlers? If so, Jelly Blast, the innovative iOS and Android game which launched last year, is worth a look. Jelly Blast sees you head off on an epic adventure through the Candy Kingdom with your friends Lily, Mr. Hare, and Mr.... | Read more »
Ellipsis - Touch. Explore. Survive. (...
Ellipsis - Touch. Explore. Survive. 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »

Price Scanner via

13-inch 1.6GHz/128GB MacBook Air on sale for...
B&H Photo has the 13″ 1.6GHz/128GB MacBook Air (sku MJVE2LL/A) on sale for $899.99 including free shipping plus NY tax only. Their price is $100 off MSRP, and it’s the lowest price available for... Read more
Sale! 27-inch 3.2GHz 5K iMac for $1799, save...
B&H Photo has the 27″ 3.2GHz/1TB Fusion 5K iMac (MK472LL/A) on sale for $1799.99 including free shipping plus NY tax only. Their price is $200 off MSRP, and it’s the lowest price available for... Read more
cb Hardcase – Handmade and Premium Protective...
Baden-Baden, Germany based company cb innovations has introduced the new cb Hardcase for iPhone. Featuring fine Italian Premium leather that makes for a unique look and feel, the cb Hardcase... Read more
Free Quartz News Aggregation App Puts News Yo...
Quartz have released their new iPhone app. via the Apple App Store. The app, exclusive to iPhone (also compatible with iPad and iPod touch.), provides a whole new way to experience Quartz, which set... Read more
Apple Watch on sale for $100 off MSRP, free s...
B&H Photo has the Apple Watch on sale for $100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - Apple Watch Sport: $100 off - Apple Watch: $100 off Read more
Sale! B&H Photo offers 12-inch Retina Mac...
B&H Photo has 12″ Retina MacBooks on sale for $300 off MSRP for a limited time. Shipping is free, and B&H charges NY tax only: - 12″ 1.1GHz Gray Retina MacBook: $999 $300 off MSRP - 12″ 1.... Read more
Save up to $470 with previous generation 27-i...
B&H Photo has previous-generation 27″ iMacs available for up to $470 off original MSRP, with prices starting at $1329. Each iMac includes free shipping, and B&H charges NY sales tax only: -... Read more
12-inch 1.1GHz Gray Retina MacBook on sale fo...
Musician’s Friend has the 12″ 1.1GHz Gray Retina MacBook on sale for $1199.99 including free shipping. Their price is $100 off MSRP, and it’s the lowest price available for this model. Read more
11-inch 256GB MacBook Air on sale for $999, $...
B&H Photo has the 11″ 1.6GHz/256GB MacBook Air on sale for $999.99 including free shipping plus NY sales tax only. That’s $100 off MSRP. MacMall has the 11″ 1.6GHz/256GB MacBook Air on sale for $... Read more
Free Reverso Context 3.1 For iOS Offers Conte...
Montreal, Canada based online and mobile translation and dictionary company Reverso has just released its Reverso Context 3.1 mobile app. The app provides its users with contextual translations of... Read more

Jobs Board

*Apple* Solution Specialist - Healthcare - C...
*Job Description* The Apple Solution Specialist - Healthcare proactively drives revenue and profit in the assigned sales segment, Healthcare, specific to Apple . This Read more
Infrastructure Engineer - *Apple* /Mac - Rem...
…part of a team Requires proven problem solving skills Preferred Additional: Apple Certified System Administrator (ACSA) Apple Certified Technical Coordinator (ACTC) Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Simply Mac *Apple* Specialist- Service Repa...
Simply Mac is the largest premier retailer of Apple products in the nation. In order to support our growing customer base, we are currently looking for a driven Read more
*Apple* Reporter - Business Insider, Inc. (U...
Business Insider is looking for a reporter to cover Apple , the biggest and arguably most important company in tech. As our primary Apple reporter, you will: * Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.