仅当行不存在时才将其追加到文件中 [英] Appending a line to a file only if it does not already exist

问题描述

我需要在配置文件的末尾添加以下行:

I need to add the following line to the end of a config file:

include "/configs/projectname.conf"

到名为lighttpd.conf

我正在考虑使用sed来做到这一点，但我不知道该怎么做.

I am looking into using sed to do this, but I can't work out how.

我如何只在行不存在的情况下插入它?

How would I only insert it if the line doesn't already exist?

推荐答案

只需保持简单:)

grep + echo 就足够了:

grep -qxF 'include "/configs/projectname.conf"' foo.bar || echo 'include "/configs/projectname.conf"' >> foo.bar

• -q安静
• -x匹配整行
• -F模式是纯字符串
• https://linux.die.net/man/1/grep
• -q be quiet
• -x match the whole line
• -F pattern is a plain string
• https://linux.die.net/man/1/grep

包含@cerin和@ thijs-wouters建议.

incorporated @cerin and @thijs-wouters suggestions.

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