$ perl --version
This is perl, v5.10.1 (*) built for x86_64-linux-gnu-thread-multi
$ echo -e "foo\nbar" > baz.txt
$ perl -p -e 's/foo\nbar/FOO\nBAR/m' baz.txt
foo
bar
How can I get this replacement to work?
我怎样才能让这个替换工作？
2 个解决方案
#1
38
You can use the -0 switch to change the input separator:
您可以使用-0开关更改输入分隔符：
perl -0777pe 's/foo\nbar/FOO\nBAR/' baz.txt
-0777 sets the separator to undef, -0 alone sets it to \0 which might work for text files not containing the null byte.
-0777将分隔符设置为undef，-0将其设置为\ 0，这可能适用于不包含空字节的文本文件。
Note that /m is needless as the regex does not contain ^ nor $.
注意/ m是不必要的，因为正则表达式不包含^也不是$。
#2
5
It has to do with the -p switch. It reads input one line at a time. So you cannot run a regexp against a newline between two lines because it will never match. One thing you can do is to read all input modifying variable $/ and apply the regexp to it. One way:
它与-p开关有关。它一次读取一行输入。所以你不能对两行之间的换行运行正则表达式，因为它永远不会匹配。您可以做的一件事是读取所有输入修改变量$ /并将正则表达式应用于它。单程：
perl -e 'undef $/; $s = <>; $s =~ s/foo\nbar/FOO\nBAR/; print $s' baz.txt
It yields:
它产生：
FOO
BAR
#1
38
You can use the -0 switch to change the input separator:
您可以使用-0开关更改输入分隔符：
perl -0777pe 's/foo\nbar/FOO\nBAR/' baz.txt
-0777 sets the separator to undef, -0 alone sets it to \0 which might work for text files not containing the null byte.
-0777将分隔符设置为undef，-0将其设置为\ 0，这可能适用于不包含空字节的文本文件。
Note that /m is needless as the regex does not contain ^ nor $.
注意/ m是不必要的，因为正则表达式不包含^也不是$。
#2
5
It has to do with the -p switch. It reads input one line at a time. So you cannot run a regexp against a newline between two lines because it will never match. One thing you can do is to read all input modifying variable $/ and apply the regexp to it. One way:
它与-p开关有关。它一次读取一行输入。所以你不能对两行之间的换行运行正则表达式，因为它永远不会匹配。您可以做的一件事是读取所有输入修改变量$ /并将正则表达式应用于它。单程：
perl -e 'undef $/; $s = <>; $s =~ s/foo\nbar/FOO\nBAR/; print $s' baz.txt
It yields:
它产生：
FOO
BAR