How to run Unix commands from within Vim?

How can I run Unix commands while I'm inside vim?

Go to command mode Esc, then run :!unix_command. Anything run from the : prompt starting with a bang ! will be run as a unix shell command. You'll be shown the output and allowed to hit a key to get back to your work in vim.

If you have text selected in visual mode and want to send it TO a command as STDIN, hit !! and enter your command. The results of the command will replace the text you have selected.

From a VIM help mirror:

:shell        :sh[ell]        start a shell
:!            :!{command}     execute {command} with a shell

If you are running neovim, or vim 8.1 or later, there is also terminal.

:terminal     :terminal {cmd}         open a terminal window

In addition to the above answers, you can use the current vim buffer content as stdin for shell command using :%!.

For example, suppose you want to filter lines from the current vim window content to contain only those with substring ca inside them. You could use:

:%! grep ca

Which will automatically filter the lines, placing the grep output instead of the current lines.

Use :!(colon bang) followed by the command you wish to run(:!{command}) to run external commands from Vim. The output of the command will then be returned for you to view. Note that you will need to wait for the command to finish running before you can continue editing because Vim is single threaded(this can be a problem with commands that take a long time to execute). See this page in the Vim help manual for further reading.