I've got a large apache log file and I have to filter might leave only (inside a new file) the log from the certain IP: 192.168.1.102

I attempt by using this command:

sed -e "/^192.168.1.102/d" < input.txt > output.txt

But "/d" removes individuals records, and that i needt to depart them.

Thanks.

How about using grep?

cat input.txt | grep -e "^192.168.1.102" > output.txt

EDIT: As noted within the comments below, getting away the dots within the regex is essential to really make it correct. Getting away within the regex is performed with backslashes:

cat input.txt | grep -e "^192\.168\.1\.102" > output.txt

sed -n 's/^192\.168\.1\.102/&/p'

sed is faster than grep on my small machines

I believe using grep is the greatest solution but when you need to use sed it can be done such as this:

sed -e '/^192\.168\.1\.102/b' -e 'd'

The b command will skip all following instructions when the regex matches and also the d command will thus remove the lines that the regex didn't match.