История изменений

Исправление xaizek, 24.06.2021 17:13 (текущая версия) :

Так и есть (variables.c:initialize_shell_variables()):

  if (current_user.euid == 0)
    bind_variable ("PS4", "+ ", 0);
  else
    set_if_not ("PS4", "+ ");

bash 4.4 ChangeLog:

g.  Shells running as root no longer inherit PS4 from the environment, closing
    a security hole involving PS4 expansion performing command substitution.

Исходная версия xaizek, 24.06.2021 17:11:

Так и есть (variables.c:initialize_shell_variables()):

  if (current_user.euid == 0)
    bind_variable ("PS4", "+ ", 0);
  else
    set_if_not ("PS4", "+ ");