Entries Tagged 'vi' ↓

Moving Around in Vim

I’ve written a couple of beginning UNIX for OS X entries, such as creating a .bash_profile and .bashrc file using vim.  Here is another vim tutorial for moving around in the screen editor, so you can see just how powerful it’s commands can be.

This post will deal with mostly command mode, the default mode when you open vim (or an existing file with it.)  To move the command marker around the file without entering INSERT mode consists of four basic keys.  Moving to the next/previous word, to the beginning of a paragraph, etc. will require a bit more memorization.

You want to first familiarize yourself with the h, j, k, and l keys.  The outer two (on a standard keyboard) move your cursor left or right one-character;  h, to the left, and l to the right.  j will move your cursor up to the next line, while k moves it down one line.  The fact that you are in command mode means no changes are made to your text at this point.  You can use the arrow keys for the same functionality, but getting used to the keys will help you keep your hands where they belong–typing and editing text.

Moving to the beginning of the current line is done by pressing O (zero).  To move to the end of the current line press $+ moves your cursor to the beginning of the next line, and – moves you to the beginning of the previous line.

Next are some basic ideas for commands.  Some will take a number argument, followed by a command.  Some can be written with a number argument followed by another command.  For example, x in command mode means delete a character.  To delete a word, or the rest of a word if you are in the middle of one, you type dw.  If you precede x with a number, n, vim will delete the following n characters from the line.  The command to delete the next four characters would be written, simply, as 4x. To delete the next four words, you would type 4dw.

Vim is a very capable text editor once you learn more about its commands, and get used to bouncing between INSERT and command modes.  Below you can find a table of common commands and their function, at least enough to get you on your way as a skilled vim user.

Movement Command

Function

h

Move Left One Character

j

Move Down One Line

k

Move Up One Line

l

Move Right One Character

0

Move to First Character Of Current Line

$

Move to Last Character Of Current Line

+

Move to First Character Of Next Line

w

Move to Next Word or Punctuation Mark

W

Move to Next Word

e

Move to End of Current Word

E

Move to End of Next Word

b

Move Back to Beginning of Word or Closest Punctuation

B

Move Back to Beginning of Word

)

Move to End of Current Sentence

(

Move to Beginning of Current Sentence

}

Move to Start if Next Paragraph

{

Move to Start of Previous Paragraph

Delete Command

Function

x

Delete Current Character

X

Delete Character Immediately Left Of Cursor

dw

Delete Current Word

10dw

Delete Ten Words

D

Delete To End of Current Line (also d$)

dd

Deletes Current Line

20dd

Deletes Twenty Lines

dG

Deletes From Cursor to End

u

Undo (doesn’t work for single character deletion)

Setup Your .bash_profile On OS X | A Sample Bash Profile

This is another addition to my entry level OS X shell category.  This one covers setting up a more detailed bash profile, so certain things are done by default when you open your Terminal.

We start by opening the Terminal in your ~/Applications/Utilities folder. If you don’t know what that means please start with this post, as it will show you a very basic beginning to the Terminal in OS X.  Be sure you are in your home directory by typing pwd at the bash prompt and hit enter.  It should look similar to this:

ssBashProfileSetup1

Next, we start vim opened to your .bash_profile.  At the bash prompt type vim .bash_profile and hit enter.  If the file exists, it will open it, if not it will create one for you.     Your Terminal window should now look like this:

vim .bash_profile

My screen shows one alias I created in my last tutorial. I like that one but technically it doesn’t belong in your .bash_profile, it belongs in a file called .bashrc. The .bash_profile is for your login shell options, and the .bashrc file is read for subsequent interactive shells;  meaning a shell opened to type commands, not just to run a script from a file automatically.  You can launch another shell on top of your login shell by typing the shell name at the prompt, i.e., bash, and then hitting enter.

This lesson will focus on login defaults, such as the PATH variable in your .bash_profile. In the process, we will be using vim, so if you are unfamiliar with that, practice makes perfect!

The PATH variable is where the system searches for binaries (shell scripts, programs, etc.) to execute.  All UNIX systems provide a default path, but you can add to it.  As you add scripts of your own creation and such, you probably want to create a directory in your home folder to store them.  This way if you screw something up, it will affect you and not the system.  For example, an erroneous rm command if you are in the /bin directory could be really bad news.

Let’s go ahead and first create a new directory called bin in your home directory.  Create a new interactive shell by pressing ⌘-N.  Type mkdir bin and hit enter.  Now type ls and hit enter.  You should see the new directory listed with your other folders:

mkdir Command

This is where you can store any shell scripts that you create, as they are easy to find in this folder.  In vim, type “i” without quotes to get you into INSERT mode.  You will see –INSERT– at the bottom of your Terminal window.  Now you can begin typing text.  You should comment your script files, and your other various profiles so you know what something does if you ever need to edit.  It’s just good programming practice to get the comments done as you progress with coding, not when you’re done!

To make a single line comment, the first character on the line needs to be the pound sign, #.  Type in #Additional binary folders, and hit enter.  Next, we set the PATH like so, to *add* to the default PATH: export PATH=$PATH:/Users/yourusername/bin

You can see in my screenshot below what the file should look like.  Replace the yourusername with your actual username for your account.  Mine is Tech, so that’s how it shows in my screenshot.  Also keep in mind, that UNIX is case-sensitive:

Bash Profile PATH

Now you can save this by hitting the escape key, and typing :w then pressing enter.  Let’s add some more commands to the profile.  We can set a welcome message to the login, and set the shell’s timer to check for new mail.  This really only matters if you use a text-only mail client, such as PINE or Alpine.  It will not affect the OS X Mail client.

Set a message to display when you login with the echo command.  This is a good command to know for the command line as well, as you can see certain system variable settings, such as your current PATH.  You can do this by typing echo $PATH at the bash prompt and hitting enter.  To use echo in your .bash_profile to set a welcome message, type echo followed by the message:

echo Welcome back, Mr Awesome!  Your present working directory is: $PWD

looks like this when you log in:

Welcome Message SetTo set the mail check timer, write a line in your .bash_profile like so:  export MAILCHECK=30

The time set is in seconds, and OS X’s bash shell by default is set to 60 seconds.  Your .bash_profile should now look similar to this:

Finished Profile Example

Next time I will cover creating a simple shell script, and changing file permissions to run them.  Also, I will try to cover some common aliases, as well as creating your .bashrc file, which is where we store the aliases.  Thanks for reading, and if you have any suggestions or questions, please feel free to ask!

Using vim In OS X — A Text Editor Tutorial For Beginners

Here is a quick tutorial for people unfamiliar with text editors in UNIX.  If you are just getting started with the Terminal in OS X, you probably need to create your .bash_profile and such, so that you can keep your settings upon logging out of the shell.  I will show you how to create this file in a text editor called vim, which stands for vi IMproved.

Vim is  a very powerful text editor, and if you have any experience in UNIX at all, you probably were shown pico, which is easier to use at first due to some of the commands being shown at the bottom of the screen as you work in pico’s buffer.  In pico, there is no separation from command or input modes, also making it a bit less confusing.  The buffer simply means what is shown on your screen, not yet written to disk.  While a GUI text editor such as Microsoft Word or Apple’s Pages do not tell you that you are working in a buffer input mode, technically it is the same thing.  If they crash, you lose what you changed if it was not saved prior to the crash.

Vim is a little obscure, yet extremely functional.  You start vim by typing vi or vim at the bash prompt in Terminal.  Terminal is located in your ~/Applications/Utilities folder by default on OS X.  When it opens, you are by default in command mode.  Vim shows you this startup screen, which has a bunch of tildes (~) on the left-hand side, and some version information in the center:

vim Startup Screen OS X Snow Leopard

vim Startup Screen OS X Snow Leopard

If you type something in, the startup screen goes away and the first tilde also disappears.  The tilde characters simply clarify lines in the buffer.  They will not print, they are just there showing you where the next lines are.  Once started, you are by default in Vim’s command mode.  If you type vim testfile.txt at the bash prompt, vim will open the file testfile.txt in whichever directory you are currently in.  If testfile.txt doesn’t exist, vim will create the file and open into the edit buffer for you, skipping the welcome screen:

Vim Buffer

Vim Buffer

As shown in the screenshot (click to enlarge it, as with all screenshots on this blog), the buffer is in INSERT mode.  By default, no matter what file you open or create, vim starts in command mode.  It doesn’t ever show —COMMAND— at the bottom of the screen.  Vim lets you know you aren’t in command mode by telling you that you are in INSERT mode.

To get back into command mode, which is where you will end up saving files to disk, changing the contents of vim’s 26 named buffers (consider them like the clipboard in a GUI text editor), moving around the screen, deleting lines, etc.  Anything you want to do with the file besides type in text will generally be done in command mode. Let’s save this file now, so you can see how it works to get in and out of command mode.

First, hit the ESC key.  On almost every keyboard ever, this will be the key  at the very top-left corner of the keyboard.  You should no longer see –INSERT– at the bottom of the Terminal window.  Now type the following command, without the quotes:  ”:w testfile.txt“.  See screenshot below:

Write Command

Write Command

File Saved

File Saved

You can see at the bottom of the Terminal window that the write command was successful.  You also see that three lines were written containing a total of 138 characters.  You can verify the file was written by typing (again, without quotes) “:q“, and hit enter.  This quits vim.  At the bash prompt, type “ls” and hit enter.  You should see your new file in the list of the directory.  To remove (delete) the file, type “rm testfile.txt” and hit enter.

Now to create your .bash_profile, so you can save certain settings.  When Terminal starts, it will read this file to load alias information, screen settings and such, if they are explained in this file.  As you become more familiar with the Terminal and start to have preferences for certain things, i.e., showing hidden files when you get a list of a directory, you may want to create an alias for the ls command so it shows them by “default” because of your .bash_profile.

First, navigate to your home directory if you are not there now.  You do this by typing the command “cd ~” at the bash prompt and hitting enter.  Terminal will show your computer name, followed by your present working directory, and yourusername$, which is the bash prompt.  You should see something like this:

Bash Prompt

Bash Prompt

Create your empty .bash_profile by typing “vim .bash_profile”  and hitting enter.  We will create a simple alias and save the profile.  Then we will quit Terminal, restart it and verify the alias still works.

Alias in Profile

Alias in Profile

By default, the alias wouldn’t work again after you quit Terminal.  If it is in your profile, it will work when you open a new Terminal, such is the point of having a profile.  To type in what I show above, press the letter “i on your keyboard to put you in insert mode.  Then type the following exactly:

dirA=”ls -lia”

Hit the ESC key, and type: “:w” to save the file.  Now type “:q” to exit vim and return to the bash prompt.  You can verify the file was written and it’s contents by typing “cat .bash_profile” and hitting enter:

Verify File Was Written

Verify File Was Written

Now quit and re-open Terminal.  You should now be able to get a detailed list of your directory, showing hidden files, by typing dirA and hitting enter:

Working dirA Alias

Working dirA Alias

Next time I will show you how to navigate through text, delete lines and add or retrieve lines to and from the named buffers.  If there are certain things you would like to learn about Terminal or vim, please leave comments below.  Please also let me know if any of this could be better clarified, as I check my comments often and will respond promptly.  Thanks for reading!