I have two text files, and I want to read file1 line by line, searching for the same line in file2 and removing it from file2.
I have the pseudocode of:
for line in file1.txt do sed search line and delete in file2.txt done 3 Answers
You could accomplish this with grep.
Here is an example:
$ echo localhost > local_hosts $ grep -v -f local_hosts /etc/hosts 127.0.1.1 ubuntu # The following lines are desirable for IPv6 capable hosts fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters Generally you want to keep the lines in file2 that are not in file1 actually.
There are more possibilities of these,
comm <(sort file1) <(sort file2) -23 via join
join -v 1 <(sort file1) <(sort file2) or via AWK which doesn't need to sort the files:
awk 'NR==FNR{lines[$0];next} !($0 in lines)' file2 file1 I found a way to do this through some more internet searches. And using just grep too without needing to sort the file.
grep -Fvxf file2 file1 This will display the new information on screen which presents a problem since I wanted to remove what was in file2 from file1 and have a new file1. Since the above code worked, I just had to add to it to get what I wanted.
grep -Fvxf file2 file1 > tempfile && mv tempfile file1 That solves my problems. Maybe not the best way but it does work.
