Vim Tips 2015-05-07
Table of Contents
Many Vim users may have, accidentally or not, discovered the dot (.) command
in Vim. It's a main stay for a lot of Vim users and is clearly one of those
actions that should be in more editors. Except when it is the wrong action for
the job.
More often than not, the visual selection mode and one-off macros are a better choice.
Visual Mode
I won't go into all of the cool things that can be accomplished with Vim's
visual mode, but I will showcase a few examples where the visual editor is
clearly a better choice than the dot (.).
Visual mode offers, in essence, a multi-line cursor for which you can do a lot of changes, quickly.
Visual Mode Basics
To enter visual mode, it is as simple as pressing ^v or ctrl-v. Next you
will want to select what you want to change with your typical movement commands
(h, j, k, l, and of course w, e and all the rest). Finally, you
finish with the action: I if you want to insert before the selection, A if
you want to append after the selection, C if you want to change the
selection, and d, D, x if you want to remove the selection, just to name
a few.
Some Examples
For (a bad) example, if you need to comment out a contiguous set of lines, you can easily accomplish this with the visual mode.
A related example to prefixing is indentation changes, I often use the visual mode to fix code indentation when changing block-level indentation or when copying code into a markdown file.
As another example, if you need to change a single word in multiple columns, visual mode will make easy work of this (especially when the columns are aligned, if not see macros below or substitution ranges from the previous tip).
For more information on Visual Mode, you can check Vim's visual help document.
Macros
For when visual mode may not be enough or when the change is repetitive in operations but not in columns or what have you, it's time to bust out the macros. Vim macros are easily available for use you can use all the registers to record and store each macro.
Macro Basics
To record a macro, it's as simple as q<register-label><commands>q. That is,
press q, select a register (a-z1-0), enter your commands as if you were using
Vim normally, and finally q again to finish. Once your macro is recorded,
you can use it with @<register-label>. And, like most Vim commands, you can
attach a repetition to it: <n>@<register-label> where <n> is the number of
times to repeat the command.
You can also replay the last macro with @@.
Some Examples
As a simplistic example, we can use a macro to convert it into, say, JSON (this example is clearly taken from the Vim Wikia).
Let's say we have the following data:
one first example two second example three third example four fourth example
And we want to change it to the following:
data = {
'one': 'first example',
'two': 'second example',
'three': 'third example',
'four': 'fourth example',
}
We can do this by performing the following:
First, we want to start recording our macro. While the cursor is under the 'o'
of 'one', we will press qd to record our macro to the d register.
Next, we will want to change the tabbing by performing a substitution:
:s/\s\+/': '
Then, we will insert our first tick with:
I'
And append the last tick and comma with:
A',
Before we finish recording, one of the more important operations of making macros repeatable is moving the cursor to the next line and putting it into the correct position for the next execution. Therefore, move the cursor the begging of the line and move down one line:
0j
Finally, press q to finish recording.
We should now be able to press 3@d and watch as the rest of the lines change.
To finish up the example, we'll manually enter data = { and the tailing }.