Vim: Open file with cursor at the end
As part of a recent quest to automate everything and learn more Vim tricks, I’ve been identifying patterns in my use of the editor and attempting to get them done with fewer keystrokes.
The Problem
I have a file containing notes which I edit several times a day. This takes quite a few keystrokes:
vim path/to/where/the/file/is/file.txt
<shift> G $
i
And then I’m ready to type. Wouldn’t it be nice to have a short alias to do that for me instead?
Choose Your Own Adventure
You can either keep reading to find out the neat but ultimately irrelevant stuff I learned along the way, or skip down to The Answer.
Techniques Available
There seem to be 4 options to accomplish this sort of task, 3 of which might be good:
- Modeline magic can potentially introduce security vulnerabilities by allowing arbitrary code to be executed, but on the positive side, it allows arbitrary configurations to be set on a per-file basis. To enable modeline hacks, add set modeline to your .vimrc then put a line of the form # vim: set expandtab: or similar in the file to which you want the command to apply.
- Autocommands allow Vim to execute specific code when it sees a particular event in the file to which they apply. To be honest, I’ve never played with autocommands before, and left them till last because they seemed to have the steepest of all 3 formidable learning curves.
- Vim’s command line options include -c {command}, which runs the specified command after the first file has been read. Or --cmd {command} executes it before processing the .vimrc file. A shorter syntax for -c is +{command}.
- The final option, which is a Wrong Answer(TM) but seems awfully tempting after the previously described ones fail a lot, is to accomplish the same purpose through circuitous bash tricks. For instance if G to jump to the end of the file fails when embedded in a command but :20 works to jump to line 20, I could use the output of wc -l as a line number. Additionally, it might be easier to have Bash concatenate on some newlines than to convince Vim to insert them.
Trying Modelines
First, I added set modeline to my .vimrc.
Then I added # vim: set noexpandtab: as the first line in my file. This is a convenient test that my command syntax is right, since my .vimrc defaults things to expandtab. It works, in that the tab key inserts hard tabs when I hit it in that particular file now.
Now, could a gesture possibly work? Switch it to # vim: G::
Error detected while processing modelines:
line 1:
E518: Unknown option: G
Press ENTER or type command to continue
Unfortunately, the :normal command which I discovered later does not work in modelines – it seems that, true to their name, they really only do take mode settings as arguments.
Trying command line syntax
I asked a few people how they solve this problem, and they suggested the vim +999999 file.txt trick. Closer examination of the man page reveals that this works because when the specified line number is absent, it defaults to the last line of the file. Although with enough 9’s it would work fine in practical applications, it seems icky to me because my notes file could hypothetically get very long. However, a quick test reveals that vim + file.txt does the same thing!
Chaining commands
Now I know that vim + file.txt opens the file with the cursor at the first character of the final line. The man page contains a promising hint that I might be able to automate switching to insert mode as well:
+{command}
-c {command}
{command} will be executed after the first file has
been read. {command} is interpreted as an Ex command.
If the {command} contains spaces it must be enclosed
in double quotes (this depends on the shell that is
used). Example: Vim "+set si" main.c
Note: You can use up to 10 "+" or "-c" commands.
I need fewer than 10 commands chained, so this might work. When looking up how to express “enter insert mode” as a command line option, I discovered the :normal command. It’s the magic bullet for allowing gestures which you’d do in normal mode to be expressed on the command line. Let’s try this:
vim "+ normal G $" file.txt
opens the file with the cursor at the last character of the last line! Success! However, "+ normal G $ i" does not put one into insert mode after moving to the last character of the file. Time to chain commands!
The Answer
vim "+normal G$" +startinsert file.txt
Does precisely what I wanted all along!
Its final form actually lives in my ~/.bashrc:
alias list='vim "+normal G$" +startinsert /absolute/path/to/list.txt'
2 hours saving 10 seconds per file open twice a day is an egregious violation of the xkcd rule, but it was fun and I learned a lot about Vim automation in the process.
Update: Mythmon pointed out that the command can be golfed into:
vim '+ normal GA' foo.txt
or to put yourself in insert mode in a new line at the end of the file:
vim '+normal Go' foo.txt