grep / awk来自第一列的另一个文件的文件中的每一行

Question

我有一个文件（file_1），我想通读并grep来自另一个文件（file_2）的每一行，但它应该只匹配该文件的第一列。

file_1

1
2
78
GL.1234
22

file_2

#blahblah hello this is some file
1 this is still some file 345
1 also still a 12 file
78 blah blah blah
22 oh my gosh, still a file!
GL.1234 hey guys, it's me. just being a file
2 i think that's it. 

输出

1 this is still some file 345
1 also still a 12 file
2 i think that's it. 
22 oh my gosh, still a file!
78 blah blah blah
GL.1234 hey guys, it's me. just being a file

我试过了：

cat file_1.txt | while read line; do awk -v line = $line '{if ($1 == line) print $0;}' < file_2.txt > output.txt; done

和

cat file_1.txt | while read line; do grep -E '$line\b' < file_2.txt > output.txt; done 

Answer 1

查看您的脚本似乎可以在一个awk中完成：

awk 'NR==FNR{seen[$1]; next} $1 in seen' file1 file2

<强>输出：

1 this is still some file 345
1 also still a 12 file
78 blah blah blah
22 oh my gosh, still a file!
GL.1234 hey guys, it's me. just being a file
2 i think that's it.

基本上，我们先扫描file并将第一列存储在关联数组seen中。稍后我们检查此数组中是否存在file2的column1并打印记录。