How to use multiline command in 'script:' with YAML?

Question

I have a repository that uses Travis CI, and in the .travis.yml there I have this line:

script:
- vim -Nu <(cat <<-EOF
  set nocompatible |
  filetype off
  EOF
  ) -c 'Script' > /dev/null

Sadly this doesn't work, as this is transformed into a single line and is executed like this:

vim -Nu <(cat <<-EOF set no compatible | filetype off | EOF ) -c 'Script' > /dev/null

This makes the EOF tag not working, as EOF needs to be in a single line. An alternative would be to just use normal quotes like this:

script:
- vim -Nu <(cat 'set nocompatible |
  filetype off
  ) -c 'Script' > /dev/null

Which works, and is fine, but I feel there must be a way to insert newlines into a .travis.yml. I have an alternative now, but I may not in the future. So how do you do it?

Answer 1

In YAML you can specify newlines in a scalar by using "" quoting and escaping the newlines (\n), or, and that is more natural for your case, by using a literal style block scalar:

script:
- |
  vim -Nu <(cat <<-EOF
  set nocompatible |
  filetype off
  EOF
  ) -c 'Script' > /dev/null

This is a scalar starting with a line with a | (pipe symbol), followed by multiple lines for which the line-breaks are preserved.

• The lines are normally indented (exception: a single top-level literal style block scalar).
• After the | there can be modifiers: 1-9, used when your first line starts with spaces; +, - to influence stripping of final newlines (normally collapsed into one).