Shell script: Replace entire line if pattern matches

Question

I've a file with this content:

# pam_faildelay.so    
auth    required    pam_faildelay.so    delay=2000000

How can I replace an entire line if it contains pam_faildelay in it? The change should not affect comments.
I tried the following command but it updates comment.

sed -i '/pam_faildelay.so/c\auth   optional   pam_faildelay.so  delay=4000000' filename

With the above command, my file looks like this:

auth   optional   pam_faildelay.so  delay=4000000
auth   optional   pam_faildelay.so  delay=4000000

Answer 1

您替换不以#开头的行：

sed ' s/^[^#]*pam_faildelay\.so.*/auth   optional   pam_faildelay.so  delay=4000000/' filename