sed 行为与 &(＆符号)

Question

试图清理一些看起来像的 xml 文本

Forest & Paper Products Manufacturing

使用 sed 命令，例如

 sed "s/ \& / & /"

但是一旦 sed 完成了文件，我的输出看起来像

Forest & amp; Paper Products Manufacturing

不明白为什么 sed 在 & 后面放一个空格

我可以解决这个问题:

sed "s/ \& / \& /"

但是为什么我需要用\前缀引用 &

Answer 1

在更换部件中，&表示匹配的字符串 \0 .所以如果你想要文字 &在替换零件中，您必须逃脱它。

例如

kent$ (master|✔) echo "foo"|sed 's/.*/&_bar/'   
foo_bar

kent$ (master|✔) echo "foo"|sed 's/.*/\&_bar/' 
&_bar

从 sed 的 INFO 页面获取的相关信息:

   The REPLACEMENT can contain `\N' (N being a number from 1 to 9,
 inclusive) references, which refer to the portion of the match which
 is contained between the Nth `\(' and its matching `\)'.  Also, the
 REPLACEMENT can contain unescaped `&' characters which reference the
 whole matched portion of the pattern space

和

To include a literal `\', `&', or newline in the final replacement, be   
 sure to precede the desired `\', `&', or newline in the REPLACEMENT with 
 a `\'.