this tells selpg to look for form feed characters in the input and treat them as the page delimiters.
该命令告诉selpg在输入中寻找换页符,并将其作为页定界符处理。
the character which when preceded by an escape character represents the form feed character.
前跟转义字符用于表示换页字符的字符。
after the lines containing text, type 2 pages only need one character -- a form feed -- to indicate the end of the page.
在含有文本的行后面,类型2 的页只需要一个字符 ―换页 ―就可以表示该页的结束。