\typein

LaTeX2e help 1.6

### 2.22.1: \typein

`\typein[cmd]{msg}`

Prints `msg` on the terminal and causes LaTeX to stop and wait for you to type a line of input, ending with return. If the `cmd` argument is missing, the typed input is processed as if it had been included in the input file in place of the `\typein` command. If the `cmd` argument is present, it must be a command name. This command name is then defined or redefined to be the typed input.