删除分隔符中的行,但匹配正则表达式的行除外

Question

我想删除两个字符串之间的所有文本,除了以某些字符串开头的行.使用下面的例子,我想摆脱串之间的文本BEGIN,并END认为是不以开头的行BREAK1或BREAK2:

keep keep keep
BEGIN
remove remove remove
remove remove remove
BREAK1 keep keep keep
remove remove remove
BREAK2 keep keep keep
remove remove remove
END
keep keep keep

有人知道我怎么能用正则表达式做到这一点？

Answer 1

perl -ne 'print if !(/^BEGIN/ .. /^END/) or /^BREAK/' file

产量

keep keep keep
BREAK1 keep keep keep
BREAK2 keep keep keep
keep keep keep

..在标量上下文是perl的触发器opeartor,并且/^BEGIN/ .. /^END/将评估为true对之间的所有行BEGIN和END包容性.