@brief Execute shell built-in or launch program. @param args Null terminated list of arguments. @return 1 if the shell should continue running,

@brief Launch a program and wait for it to terminate. @param args Null terminated list of arguments (including program). @return Always returns 1,

@brief Loop getting input and executing it. */

@brief Read a line of input from stdin. @return The line from stdin. */

@brief Split a line into tokens (very naively). @param line The line. @return Null-terminated array of tokens. */

@brief Builtin command: change directory. @param args List of args. args[0] is "cd". args[1] is the directory. @return Always returns 1, to co

@brief Builtin command: exit. @param args List of args. Not examined. @return Always returns 0, to terminate execution. */

@brief Builtin command: print help. @param args List of args. Not examined. @return Always returns 1, to continue executing. */

@brief Main entry point. @param argc Argument count. @param argv Argument vector. @return status code */