grep lines in file that consist only of a given string

Question

I am using the following

grep -rn "activity" * to return lines in files of a subdirectory. I get things like:

There was no activity
We reported no activity
There was some activity

I now want to limit this to lines where the only string is the word activity . All my searches seem to find limiting the output to the string itself, not the actual line that only consists of the string itself.

Any help would be great!

Answer 1

grep can be combined with a concept called regular expressions or re's for short. The following line should do the trick:

grep -rn "^activity$" *

^ - matches the beginning of the line.

$ - matches the end of the line.

Answer 2

grep has a --line-regex flag (shortened into -x ) that does exactly what you need : when provided, the pattern activity will only match whole lines consisting of only "activity".

$ echo "There was no activity
We reported no activity
activity" | grep -x activity

activity

In your case, using grep -rxn activity * should do the trick.