![]() Each entry in the command table follows the format of command name, is the command built-in (ie can the command run in the background), and the function that executes the command. Next, the command is looked up in the command table defined at the top of shell/shell.c. The shell is designed to handle redirection, but does not currently do so since XINU's file system is in development. The shell first checks for the backgrounding ampersand ('&'), which should only appear as the last token. Command name, arguments, quoted strings, backgrounding, and redirection tokens are all recognized and divided by lexan.Īfter the command is parsed, the shell uses the tokens to properly execute the given command. When a user enters a command the lexan function divides the string of input into tokens. When XINU starts, a shell process is spawned for each serial port (or TTY). The shell relies on the TTY driver to receive user input and provide output to the user. ![]() 3.4.3 Add the function prototype to the include file.3.4.2 Add the function to the command table.
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