如何使用 grep 将一个文件中的子字符串匹配到另一个文件？

Question

I have two files. File1 with bunch of email address. File2 with list of domains.

I want to find all the email address matching the domains (also the non-matching ones)

If some one please let me know how can we do this using 'grep' from terminal.

File1.csv
abc@gmail.com
abc@fmail.com
abc@fb.com
abc@hotmail.com
abc@outlook.com
abc@live.com

File2
hotmail.com
live.com
fb.com

The output should be (and non-matching as well)
abc@fb.com
abc@hotmail.com
abc@live.com

Please consider the email file is too big and contains 2M emails to compare against 6k domains.

Answer 1

您可以使用 -f 从文件中读取模式：

grep -f File2 File1.csv

Answer 2

In your comment, you are trying to match a fixed pattern of: @[anydomainNameInFile2.txt]

in this case, you might need to add @ at the beginning of each line in File2 so you can use it as a fixed pattern.

you can do it by the following:

1. add @ at the beginning of each line in file2.txt using sed command.

    $ sed 's/^/@/' file2.txt > new-file.txt

don't worry that won't miss with your main file, you are saying it's about 2M field, we are saving the output to another file named new-file.txt

2. run the -f option grep command using the new-file.txt file as the following:

    $ grep -f newfile.txt File1.csv