You are not inside the directory that the file `string` or `initials` is. You have to get in the directory that the file `string` or `initials` is in, which is `pset2`, assuming you have kept the files in the folder `pset2`.

A simple way to do this is `cd pset2` and then you may execute `./initials` or `./string`. 

Your current directory, `workspace` is looking for a file called `string` or `initials` within `workspace`, not within `workspace/pset2`. The computer is very strict about the folders, files, and directories.

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