Batch file 批处理文件，仅将findstr结果的第一个匹配项打印到文本文件

我正在尝试编写一个批处理文件，从fileA.txt读取列表，然后检查fileC.txt是否存在匹配项，如果不存在匹配项，则只将第一行匹配项从fileB.txt写入fileC.txt

aaa1 some text
aaaa some info
aaaa4 some name
bbb some name to
ccc12 another name

fileA.txt示例

aaa1
aaaa
aaaa4
bbb
ccc12

aaa1 some text
aaa1 blah bla
aaa1 .r
aaaa some info
aaaa blah bla
aaaa4 some name
bbb some name to
bbb more blah blah
ccc12 another name
ccc12 blah bla

fileB.txt示例

aaa1
aaaa
aaaa4
bbb
ccc12

aaa1 some text
aaa1 blah bla
aaa1 .r
aaaa some info
aaaa blah bla
aaaa4 some name
bbb some name to
bbb more blah blah
ccc12 another name
ccc12 blah bla

结果文件c.txt

aaa1 some text
aaaa some info
aaaa4 some name
bbb some name to
ccc12 another name

我想做什么

for /F %%i in (C:\filecopy\fileA.txt) do (
If exist (findstr /B /C:%%i fileC.txt) (
echo %%i exists ) else (
findstr /B /C:%%i fileB.txt >> fileC.txt )
)

---

但是，该代码不正确，我不确定如何最好地处理它。解决方法是在fileB.txt中搜索fileA.txt中的每个单词时，将findstr结果的第一个匹配项存储在fileC.txt中（正如您在问题标题中所指出的）：