executes the command specified by the user. This will require parsing what the user has entered into separate tokens and storing the tokens in an array of character strings ( args in Figure 3.36). For example, if the user enters the command ps -ael at the osh> prompt, the values stored in the args array are: args = "ps" args = "-ael" args = NULL This args array will be passed to the execvp() function, which has the following prototype: execvp(char *command, char *params); Here, command represents the command to be performed and params stores the parameters to this command. For this project, the execvp() function should be invoked as execvp(args, args) . Be sure to check whether the user included an & to determine whether or not the parent process is to wait for the child to exit. Part II—Creating a History Feature The next task is to modify the shell interface program so that it provides a history feature that allows the user to access the most recently entered commands. The user will be able to access up to 10 commands by using the feature. The commands will be consecutively numbered starting at 1, and the numbering will continue past 10. For example, if the user has entered 35 commands, the 10 most recent commands will be numbered 26 to 35.
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- Fall '09
- Exit, Child process