How do I run commands automatically when certain events occur?

Explanation

Autocommands let you execute commands automatically in response to events like opening a file, saving, or changing buffers.

How it works

• :autocmd BufWritePre * :%s/\s\+$//e removes trailing whitespace before saving
• :autocmd FileType python setlocal tabstop=4
• The event triggers the command on matching files

Example

autocmd BufWritePre *.go :silent !gofmt -w %
autocmd FileType javascript setlocal shiftwidth=2
autocmd BufNewFile *.py :r ~/templates/python.py

Tips

• Use augroup to organize and prevent duplicate autocommands
• :autocmd! inside a group clears previous commands
• Common events: BufRead, BufWrite, FileType, InsertLeave
• :autocmd with no arguments lists all autocommands
• :help autocmd-events lists all available events