您可以使用两个地址的形式：

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

这将删除该模式的第一次出现。

引用自info sed：

 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.