为什么SSH远程命令会在手动运行时获得更少的环境变量?

 2019-09-09 

Why does an SSH remote command get fewer environment variables then when run manually?

我有一个运行正常的命令,如果我ssh到一台机器并运行它,但当我尝试使用远程ssh命令运行它时失败,如:

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ssh user@IP <command>

使用两种方法比较"env"的输出在不同环境中重新进行。 当我手动登录到机器并运行env时,我运行时会获得更多的环境变量:

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ssh user@IP"env"

知道为什么吗?


有不同类型的贝壳。 SSH命令执行shell是非交互式shell,而普通shell是登录shell或交互式shell。描述如下,来自man bash:

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       A  login  shell  is  one whose first character of argument
       zero is a -, or one started with the --login option.

       An interactive shell is  one  started  without  non-option
       arguments  and  without the -c option whose standard input
       and error are both connected to terminals  (as  determined
       by  isatty(3)), or one started with the -i option.  PS1 is
       set and $- includes i if bash is interactive,  allowing  a
       shell script or a startup file to test this state.

       The  following  paragraphs  describe how bash executes its
       startup files.  If any of the files exist  but  cannot  be
       read,  bash reports an error.  Tildes are expanded in file
       names as described below  under  Tilde  Expansion  in  the
       EXPANSION section.

       When  bash is invoked as an interactive login shell, or as
       a non-interactive shell with the --login option, it  first
       reads and executes commands from the file /etc/profile, if
       that file exists.  After reading that file, it  looks  for
       ~/.bash_profile,  ~/.bash_login,  and  ~/.profile, in that
       order, and reads and executes commands from the first  one
       that  exists  and is readable.  The --noprofile option may
       be used when the shell is started to inhibit  this  behav-
       ior.

       When a login shell exits, bash reads and executes commands
       from the file ~/.bash_logout, if it exists.

       When an interactive shell that is not  a  login  shell  is
       started,  bash reads and executes commands from ~/.bashrc,
       if that file exists.  This may be inhibited by  using  the
       --norc  option.   The --rcfile file option will force bash
       to  read  and  execute  commands  from  file  instead   of
       ~/.bashrc.

       When  bash  is  started  non-interactively, to run a shell
       script, for example, it looks for the variable BASH_ENV in
       the  environment,  expands  its value if it appears there,
       and uses the expanded value as the name of a file to  read
       and  execute.   Bash  behaves  as if the following command
       were executed:
              if [ -n"$BASH_ENV" ]; then ."$BASH_ENV"; fi
       but the value of the PATH variable is not used  to  search
       for the file name.


在运行命令之前如何获取配置文件?

ssh user@host"source /etc/profile; /path/script.sh"

您可能会发现最好将其更改为~/.bash_profile~/.bashrc或其他任何内容。

(如此(linuxquestions.org))


运行远程ssh命令时不加载Shell环境。您可以编辑ssh环境文件:

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vi ~/.ssh/environment

其格式为:

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VAR1=VALUE1
VAR2=VALUE2

另外,检查PermitUserEnvironment = yes选项的sshd配置。


我有类似的问题,但最后我发现?/ .bashrc就是我所需要的。

但是,在Ubuntu中,我不得不评论停止处理?/ .bashrc的行:

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#If not running interactively, don't do anything
[ -z"$PS1" ] && return


我发现这个问题很容易解决
源/ etc / profile
到script.sh文件的顶部我试图在目标系统上运行。
在这里的系统上,这导致script.sh所需的环境变量被配置为好像从登录shell运行。

在之前的一个回复中,建议使用?/ .bashr_profile等。
我没有花太多时间在这上面,但问题是,如果你在目标系统上ssh到另一个用户而不是从你登录它的源系统上的shell看起来这会导致源系统用户用于?的名称。


只需在?/ .bashrc中检查非交互式shell的上方导出所需的环境变量。