如何在sed中插入包含反斜杠的变量? [英] How can I insert a variable containing a backslash in sed?

问题描述

请查看以下简单命令:

$ echo $tmp
UY\U[_
$ echo "a" | sed "s|a|${tmp}|g"
UY[_

\U被吃掉了.其他反斜杠也将无法生存.

The \U is eaten. Other backslashes won't survive either.

如何使上述命令按预期工作?

How can I make the above command work as expected?

推荐答案

如果只有sed被吃"了反斜杠并转义就足够了，请尝试:

If it's only backslash that is "eaten" by sed and escaping just that is enough, then try:

echo "a" | sed "s|a|${tmp//\\/\\\\}|g"

让您感到困惑吗? \\表示单个\，因为它也需要在外壳中转义. 初始//类似于s/foo/bar/g中的g修饰符，如果您只想替换第一个出现的模式，请跳过它.

Confusing enough for you? \\ represents a single \ since it needs to be escaped in the shell too. The inital // is similar to the g modifier in s/foo/bar/g, if you only want the first occurring pattern to be replaced, skip it.

有关${parameter/pattern/string}的文档位于此处: http://www.gnu.org/s/bash/manual/bash.html#Shell-Parameter-Expansion

The docs about ${parameter/pattern/string} is available here: http://www.gnu.org/s/bash/manual/bash.html#Shell-Parameter-Expansion

编辑:根据您要执行的操作，最好不为此实际使用sed.

Depending on what you want to do, you might be better of not using sed for this actually.

$ tmp="UY\U[_"
$ in="a"
$ echo ${in//a/$tmp}
UY\U[_

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