COMMAND 命令与直接在shell输入的命令有什么区别?

COMMAND 命令与直接在shell输入的命令有什么区别?　　　　　　

man command查command, 里头有详细的

电脑出了点问题， 死活不能粘贴， 呵

　　　　　　

command [-pVv] command [arg ...]
              Run  command  with args suppressing the normal shell function lookup. Only builtin commands or commands found in the PATH are executed.  If the -p option is given, the search for command is per-
              formed using a default value for PATH that is guaranteed to find all of the standard utilities.  If either the -V or -v option is supplied, a description of command is printed.   The  -v  option
              causes  a single word indicating the command or file name used to invoke command to be displayed; the -V option produces a more verbose description.  If the -V or -v option is supplied, the exit
              status is 0 if command was found, and 1 if not.  If neither option is supplied and an error occurred or command cannot be found, the exit status is 127.  Otherwise, the exit status of  the  com-
              mand builtin is the exit status of command.
理解不透,请详细解释并举例.
谢谢!　　　　　　

关键是这句话 　　　　　　

明白了,十分感谢!