What keyword is missing from this code sample of a shell script? ____ i in *.txt; do echo $i done

In shell scripting, `for i in *.txt; do echo $i; done` is the standard syntax for a `for` loop that iterates through all files matching the pattern `*.txt`, assigning each filename to the variable `i` for processing within the loop's `do...done` block. The `for` keyword introduces this iterative control structure.

`loop` is not a standard keyword for creating iterative loops in bash scripting; it is often part of a loop's description, not its syntax.

`until` is a keyword used for a loop that continues until a condition becomes true, with a different syntax (`until condition; do commands; done`).

`while` is a keyword used for a loop that continues as long as a condition is true, also with a different syntax (`while condition; do commands; done`).