Getting a language manual in Vim
The K command opens in a new buffer the manual of the word under the
cursor.
For example, if the edited file is a C, or a bash file, pressing K on a
command will open man <the-command>. If the edited file is a python file,
pressing K will open pydoc.
Set custom help commands
First you need to have the filetype plugin enabled in vim, to do so, add the
following line in your .vimrc:
filetype plugin on
Then, create the directory ~/.vim/ftplugin/. In this directory, you can
add vimscripts executed only for the desired filetypes. For example, if you want
some script and configuration for PHP only, create the directory
~/.vim/ftplugin/php/ and any vim script in it will be executed only when
editing PHP files.
So, let’s say we want to open php.net when pressing K
on a function in a PHP file.
First we need to create a program to open php.net:
#!/bin/bash
firefox https://php.net/$1 &
Then, we need to define in Vim that K must run the previously created
script instead of man in PHP files. For that, create a .vim script
in ~/.vim/ftplugin/php/ with the following line:
set keywordprg='/path/to/the/bash/script/above'
From this point, if you press K in a php file, it will open php.net.