Which grep command will print only the lines that do not end with a / in the file foo?

`grep '/$' foo` would print lines that *do* end with a '/', which is the opposite of the question's requirement.

`grep '/#' foo` searches for lines containing the literal string '/#', and `#` does not represent the end of a line in `grep` regular expressions.

The `grep -v` command is used to invert the match, meaning it prints lines that *do not* match the specified pattern. The regular expression `/$` matches lines that end with a forward slash (`/`), as `$` signifies the end of a line. Therefore, `grep -v '/$' foo` prints all lines from the file 'foo' that do not end with a '/'.

`grep -v '/#' foo` would print lines that *do not* contain the literal string '/#', which does not fulfill the condition of not ending with a '/'.