your questions makes zero sense
enter
Alt and Ctrl key are special keys. Then can be used as quick menu button or can be used to execute a program. You can also use them to do a shortcut key command.
the command is not available it is used in windows.its means at time execute command
apachectl start
system
There is no traditional 'execute' command in Unix.
You can right-click on an appropriate object to select a command, then right-click to execute the command. You can click on an icon to execute some commands.
It will depend on the software being used but is often the Command and R keys.
that is the command for system file checker.
Command prompt/line is used to execute entered commands. Command prompt is mostly commonly used to execute batch files, perform advanced administrative functions, and troubleshoot and solve certain kinds of windows issues.
You can schedule jobs using cron and the /etc/crontab file, or you can use the "at" command
Built-in commands are not strictly necessary. However, if is a commonly used command you will get a performance benefit from having the shell execute it directly rather than doing a file system search to find the program to execute the command.