I have a list of a million domain names in name.txt
hello.com
abc.com
gogogo.us
goodbye.me
...
...
How do I pipe only domain names with 8 letters (including the .com
) and only ends in .com
to names_new.txt
?
I'm looking for a simple command and not a script or anything.
grep
是第一个用于模式匹配的工具:
egrep -x '[a-z]{4}\.com' name.txt > newname.txt
尝试
egrep "^[a-z][a-z][a-z][a-z]\.com$" name.txt > names_new.txt
Use Awk. The domain name is split by .
into fields.
First field is tested for length 4,as the .com
adds another 4 chars.
The second field should contain com
.
When both conditions are met, the line is printed.
cat name.txt |awk -F. '((length($1)==4)&&($2=="com")){print;}' > names_new.txt
Note: the line may found false positives if you have subdomains, eg: mail.com.nz
There may be domain names with dashes or numbers.
-i forces egrep to match regardless of case.
egrep -i "^[a-z0-9-]{4}\.com$" name.txt > names_new.txt
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