SHELL_SCRIPT
  COMMANDS_LIST
    GENERIC_COMMAND_DIRECTIVE
      STRING
        PsiElement(OPEN_QUOTE)('"')
        VARIABLE
          PsiElement(var)('$a')
        PsiElement(CLOSE_QUOTE)('"')
  PsiElement(\n)('\n')
  COMMANDS_LIST
    GENERIC_COMMAND_DIRECTIVE
      STRING
        PsiElement(OPEN_QUOTE)('"')
        PsiElement($)('$')
        SUBSHELL_COMMAND
          PsiElement(()('(')
          COMPOUND_LIST
            GENERIC_COMMAND_DIRECTIVE
              LITERAL
                PsiElement(word)('echo')
          PsiElement())(')')
        PsiElement(CLOSE_QUOTE)('"')
  PsiElement(\n)('\n')
  COMMANDS_LIST
    GENERIC_COMMAND_DIRECTIVE
      STRING
        PsiElement(OPEN_QUOTE)('"')
        PsiElement($)('$')
        SUBSHELL_COMMAND
          PsiElement(()('(')
          COMPOUND_LIST
            GENERIC_COMMAND_DIRECTIVE
              NUMBER
                PsiElement(int)('123')
          PsiElement())(')')
        PsiElement(CLOSE_QUOTE)('"')
  PsiElement(\n)('\n')
  COMMANDS_LIST
    GENERIC_COMMAND_DIRECTIVE
      STRING
        PsiElement(OPEN_QUOTE)('"')
        PsiElement($)('$')
        ARITHMETIC_EXPANSION
          PsiElement(()('(')
          PsiElement(()('(')
          LITERAL_EXPRESSION
            PsiElement(word)('a')
          PsiElement())(')')
          PsiElement())(')')
        PsiElement(CLOSE_QUOTE)('"')