如何使用sed仅删除文件中第一个出现的行 [英] How to remove only the first occurrence of a line in a file using sed

问题描述

我有以下文件

titi
tata
toto
tata

如果我执行

sed -i "/tat/d" file.txt

它将删除所有包含tat的行.该命令返回:

It will remove all the lines containing tat. The command returns:

titi
toto

但是我只想删除包含tat的文件中出现的第一行:

but I want to remove only the first line that occurs in the file containing tat:

titi
toto
tata

我该怎么办?

推荐答案

您可以使用两个地址的形式:

You could make use of two-address form:

sed '0,/tat/{/tat/d;}' inputfile

这将删除模式的首次出现.

This would delete the first occurrence of the pattern.

从info sed报价:

 A line number of `0' can be used in an address specification like
 `0,/REGEXP/' so that `sed' will try to match REGEXP in the first
 input line too.  In other words, `0,/REGEXP/' is similar to
 `1,/REGEXP/', except that if ADDR2 matches the very first line of
 input the `0,/REGEXP/' form will consider it to end the range,
 whereas the `1,/REGEXP/' form will match the beginning of its
 range and hence make the range span up to the _second_ occurrence
 of the regular expression.

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