The \fill-line command

The \fill-line command aligns and justifies markup text by setting as many columns as required, in a given space.

In this snippet we use numbers to (beautifully) show how the command works; but when using text beware to use quotes if you want your words to stay together:

\fill-line {The quick brown fox}
results in something like:

The quick brown fox

\fill-line {"The quick brown fox"}
results in something like:

The quick brown fox

\version "2.24.0"

%% http://lsr.di.unimi.it/LSR/Item?id=244

\paper {
  line-width = 15\cm
  bookTitleMarkup = \markup {
    \column {
      \fill-line {
        1
      }
      \fill-line {
        1
        2
      }
      \fill-line {
        1
        2
        3
      }
      \fill-line {
        1
        2
        3
        4
      }
      \fill-line {
        1
        2
        3
        4
        5
      }
      \fill-line {
        1
        2
        3
        4
        5
        6
      }
      \fill-line {
        1
        2
        3
        4
        5
        6
        7
      }
      \fill-line {
        1
        2
        3
        4
        5
        6
        7
        8
      }
      \fill-line {
        1
        2
        3
        4
        5
        6
        7
        8
        9
      }
      \fill-line {
        1
        2
        3
        4
        5
        6
        7
        8
        9
        10
      }
      \fill-line {
        1
        2
        3
        4
        5
        6
        7
        8
        9
        10
        11
      }
      \fill-line {
        1
        2
        3
        4
        5
        6
        7
        8
        9
        10
        11
        12
      }
      \fill-line {
        1
        2
        3
        4
        5
        6
        7
        8
        9
        10
        11
        12
        13
      }
      \fill-line {
        1
        2
        3
        4
        5
        6
        7
        8
        9
        10
        11
        12
        13
        14
      }
    }
  }
}

\score {
  \new Staff \relative c'' {
  \repeat unfold 4 c1
  }
}