bash - How to grep for case insensitive string in a file?

Question

I have a file file1 which ends with Success... OR success...

I want to grep for the word success in a way which is not case sensitive way.

I have written the following command but it is case sensitive

cat file1 | grep "success..."

How can i change it so that it returns 0 with both Success... OR success...

Answer 1

You can use the -i flag which makes your pattern case insensitive:

grep -iF "success..." file1

Also, there is no need for cat. grep takes a file with the syntax grep <pattern> <file>. I also used the -F flag to search for a fixed string to avoid escaping the ellipsis.