How can I check if the current shell is being used from vim?

I am running OS X. On vim, if you do the :sh command, you can drop to a shell to execute commands. I constantly forget whether I am in this shell or not.

Is there any way to check if I am in the shell coming from vim?

Wuffers

Posted 2010-10-17T16:38:14.277

Reputation: 16 645

Answers

env | grep vim lists environment variables that vim passes to your shell. I doubt VIMRUNTIME is defined if you haven't started your shell from vim.

Benoit

Posted 2010-10-17T16:38:14.277

Reputation: 6 563

4Awesome, this worked. I simply set it up to display {vim} in my PS1 if VIMRUNTIME is defined. Thanks! – Wuffers – 2010-10-17T17:39:54.957

I type ps (without any options) and see if vim is listed.

RedGrittyBrick

Posted 2010-10-17T16:38:14.277

Reputation: 70 632

at least use pstree, if there is more than one instance of vim. – Benoit – 2010-10-17T17:16:56.607

@Benoit: ps alone should be sufficient because by default it shows only those processes associated with the current terminal. At least that's the case on the Unix systems I use. – garyjohn – 2010-10-17T17:29:53.363

You can look at the command name of the shell's parent process: ps -o comm= -p $PPID. You could for example change your prompt to include the parent process id.

Furthermore, if you only want to change your prompt in shells that are not running directly inside a terminal emulator, you can test this by checking whether the shell's controlling terminal is the same as its parent process's. If the parent is a terminal emulator, it won't have its own terminal as a controlling terminal.

For example, if you put the following lines in your ~/.kshrc or ~/.bashrc or ~/.zshrc (pick the one appropriate for your shell), your prompt will begin with {vim} if the shell is running under vim:

parent_command=$(ps -o comm= -p $PPID)
parent_command=${parent_command##*/}
if [ "$(ps -o tty= -p $$)" = "$(ps -o tty= -p $PPID)" ]; then
  # Not running directly under a terminal emulator
  PS1="{$parent_command}$PS1"
fi

You may also be interested in some of the discussion on How to know the “level” of shells I am in?.

Gilles 'SO- stop being evil'

Posted 2010-10-17T16:38:14.277

Reputation: 58 319

Whenever I do this, and I am in the vim shell, I get {%cpu} instead of {vim}. And If I'm not in vim, I get errors at login. – Wuffers – 2010-10-17T17:35:59.300

@Mr. Man: What I wrote should work under any POSIX-compliant OS (-o cmd= means not to display a header line, but getting %cpu means that ps did show a header line). However ps differs a lot between platforms, maybe yours isn't 100% compliant. What OS is it? – Gilles 'SO- stop being evil' – 2010-10-17T17:41:04.870

I am running Mac OS X. And, if it matters, I am using the provided Terminal.app. – Wuffers – 2010-10-17T18:02:06.543

@Mr. Man: My mistake, the comm column is standard (and documented on OSX) but cmd isn't. You might still need $(ps -o comm= -p $PPID | tail -n 1) on OSX ≤10.4. – Gilles 'SO- stop being evil' – 2010-10-17T18:27:38.663

Thanks, that fixed the errors, but now when I am in the vim shell, it only shows {} instead of {vim}. – Wuffers – 2010-10-17T18:32:58.987

You could use MacVim (http://code.google.com/p/macvim/). Whether or not your shell came from a vim instance becomes pretty obviously since your shell is in a MacVim window and not a Terminal window.

whaley

Posted 2010-10-17T16:38:14.277

Reputation: 1 376