使用ps ef还是ps -ef？

Question

我看到了ps ef和ps -ef在输出方面的不同。有什么区别，这两个命令是正确的还是谁是首选？

Answer 1

请参阅man ps (在您的系统上，在线可以有不同的解释)。

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，第一个方法(ps ef)是BSD样式，手册页接着是

使用BSD样式选项将向默认显示中添加进程状态(stat=STAT)，并显示命令args (args=COMMAND)而不是可执行名称。您可以使用PS_FORMAT环境变量重写此操作。使用BSD样式的选项还将更改流程选择，以包括您拥有的其他终端(TTY)上的进程；或者，这可以描述为将选择设置为筛选的所有进程的集合，以排除其他用户拥有的进程或终端上的进程。当选项在下面被描述为“相同”时，不考虑这些影响，因此-M将被认为与Z相同等等。

因此，这两个命令都是有效的，但它们显示的信息并不相同。

Answer 2

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，-ef使用Unix -e和-f选项。这些不同(分别是SIMPLE PROCESS SELECTION、OUTPUT FORMAT CONTROL和OUTPUT MODIFIERS部分)：

   -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，外加一些附加格式：

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.

你应该用哪一种？你想用输出做什么？

另外，请参阅EXAMPLES部分(它非常突出地列出了-ef，并且根本没有使用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