Tricky #ao7 case "^dog$" not matching "dogdogdog"

[HowieTKL]

According to grep behavior:

echo dogdogdog | grep -E "^dog$"

does NOT match. However, individually ^dog and dog$ will match dogdogdog. I do not believe the test cases capture this seemingly quirky scenario either.

But I’m stumped trying to mimic grep behavior for ^dog$ with dogdogdog. It does not seem possible by simply checking string “starts with” dog for ^ and “ends with” dog for $. Anyone have any insights on how to think about ^$?

[andy1li]

Anyone have any insights on how to think about ^$ ?

Hey @HowieTKL, a helpful way to think about ^$ is that it means match the entire line exactly.

Namely, the pattern ^dog$ is equivalent to line == "dog":

[HowieTKL]

Thanks @andy1li - just refining what you said: I think ^ can be read as “matches exactly from the start” and $ as “matches exactly from the end”.