The Vim text editor has its roots in the traditional line-based editors of the early days. Due to that heritage, it supports a set of impressively powerful Ex commands that act on individual lines. In this article, we will see how to create a script composed of these commands and execute it from the shell.

Ex mode

If you would like to see the ‘original’ ex editor in action, you can call vim with the -e option:

vim -e <demo.txt>

In this mode, you can’t even see the actual file content yet – probably that’s why it’s called line-based. To print all lines, enter %print at the Ex prompt. The % character means “all lines”. In contrast, 1print shows just the first line of the file.

But it’s not only the traditional ex commands that are supported; you can also apply Vim normal mode commands to a range of lines. For example, %normal Afoo would append the word ‘foo’ to all lines of the file.

This is great news: We can solve an editing problem in interactive Vim, store the commands and apply it to thousands of instances of the same problem afterwards.

Executing Ex scripts

Let’s see how we can do this step-by-step. First, we will create a file demo.txt:

foo bar
bar foo

As an example, we’re going to convert the words in the second column to uppercase so the converted file would look like:

foo BAR
bar FOO

In interactive Vim, we might end up applying the sequence wgUW to both of the lines in the file, starting from the leftmost column. This would scale perfectly to N lines, so let’s put it into a script and call it commands.vim:

%normal wgUW

After that, we start Vim in silent Ex mode and pass the script contents via stdin:

cat commands.vim | vim -es demo.txt

We may also loop through a list of files:

for f in *.txt; do
	cat commands.vim | vim -es "$f"

We could even place the commands right into a bash script, using a “Here document”, if that’s desirable:

vim -es demo.txt <<EOF
	%normal wgUW

Conclusion, References

Scripting Vim might be a good alternative to using sed and awk, provided that you are familiar with that editor anyway.

Below you will find some resources worth reading.