使用哪个ps ef或ps -ef？

我发现ps ef和之间的输出有所不同ps -ef。有什么区别，两个命令都是正确的还是首选？

请参阅man ps（系统上的一个，在线可能有不同的解释）。

This version of ps accepts several kinds of options:

   1   UNIX options, which may be grouped and must be preceded by a dash.
   2   BSD options, which may be grouped and must not be used with a dash.
   3   GNU long options, which are preceded by two dashes.

因此，第一种方法（ps ef）是BSD样式，并且手册页继续

使用BSD样式的选项会将进程状态（stat = STAT）添加到默认显示，并显示命令args（args = COMMAND）而不是可执行文件名。您可以使用PS_FORMAT环境变量覆盖它。使用BSD样式的选项还将更改过程选择，以包括您拥有的其他终端（TTY）上的过程；替代地，这可以被描述为将选择设置为被过滤以排除其他用户拥有的或不在终端上的进程的所有进程的集合。当以下将选项描述为“相同”时，不会考虑这些效果，因此-M将被视为与Z相同，依此类推。

因此，两者都是有效的命令，但是它们没有显示相同的信息。

man ps 说：

This version of ps accepts several kinds of options:

1   UNIX options, which may be grouped and must be preceded by a
    dash.
2   BSD options, which may be grouped and must not be used with a
    dash.
3   GNU long options, which are preceded by two dashes.

因此，ef使用BSD e和f选项，并-ef使用Unix -e和-f选项。这些是不同的（部分SIMPLE PROCESS SELECTION，OUTPUT FORMAT CONTROL和OUTPUT MODIFIERS分别地）：

   -e     Select all processes.  Identical to -A.
   -f     Do full-format listing. This option can be combined with many
          other UNIX-style options to add additional columns.  It also
          causes the command arguments to be printed.  When used with
          -L, the NLWP (number of threads) and LWP (thread ID) columns
          will be added.  See the c option, the format keyword args, and
          the format keyword comm.

   e      Show the environment after the command.

   f      ASCII art process hierarchy (forest).

显然，您不是使用ef选项选择所有进程，而是使用默认的进程列表以及一些其他格式：

By default, ps selects all processes with the same effective user ID
(euid=EUID) as the current user and associated with the same terminal
as the invoker.  It displays the process ID (pid=PID), the terminal
associated with the process (tname=TTY), the cumulated CPU time in
[DD-]hh:mm:ss format (time=TIME), and the executable name (ucmd=CMD).
Output is unsorted by default.

The use of BSD-style options will add process state (stat=STAT) to
the default display and show the command args (args=COMMAND) instead
of the executable name.  You can override this with the PS_FORMAT
environment variable. The use of BSD-style options will also change
the process selection to include processes on other terminals (TTYs)
that are owned by you; alternately, this may be described as setting
the selection to be the set of all processes filtered to exclude
processes owned by other users or not on a terminal.

您应该使用哪个？您要如何处理输出？

另外，请参见本EXAMPLES节（该清单列出的位置-ef非常突出，根本不使用BSD e选项）：

EXAMPLES

   To see every process on the system using standard syntax:
      ps -e
      ps -ef
      ps -eF
      ps -ely

   To see every process on the system using BSD syntax:
      ps ax
      ps axu

   To print a process tree:
      ps -ejH
      ps axjf