Double and single horizontal bars in Shell Parameters

ShellA process is a process that executes other processes, but when executing a command,ShellThe process instructs the kernelProgramRun the command separately as another process and write the output to the terminal. Through Command Options, we can modify the command execution behavior. Command line options can be divided into short command line options and long command line options. The short command line option is composed of letters, and the long command line option is composed of words. The short command line option uses the horizontal bar"-", Use the horizontal bars before the long command line option"--". If you need to enter the option parameter after the option, the short command line option and the parameter are separated by spaces, while the long command line option uses the equal sign"="Connection options and parameters. Add the option"-- Help","-H"Or"-?", We can get help information for a command.