为什么SSH远程命令得到的环境变量比手动运行时少?

我有一个命令，运行良好，如果我ssh到一台机器并运行它，但失败时，我试图运行它使用远程ssh命令，如:

ssh user@IP <command>

比较使用这两种方法的“env”的输出会得到不同的环境。当我手动登录到机器并运行env时，我得到了比运行时更多的环境变量:

ssh user@IP "env"

知道为什么吗?

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最佳答案

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

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.
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在运行命令之前如何获取概要文件?

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

你可能会发现最好将其更改为~/.bash_profile， ~/.bashrc或其他。

(如在这里(linuxquestions.org))

小开

我也有类似的问题，但最后我发现~/。bashrc是我所需要的。

但是，在Ubuntu中，我必须注释停止处理~/的行。bashrc: (

#If not running interactively, don't do anything
[ -z "$PS1" ] && return
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我发现一个简单的解决这个问题的方法是添加 源/ etc / profile 到我试图在目标系统上运行的script.sh文件的顶部。 在这里的系统上，这会导致script.sh所需的环境变量被配置为从登录shell中运行

在先前的一个响应中，建议~/。bashr_profile等等……被使用。 我没有花太多时间在这上面，但是，问题是，如果您ssh到目标系统上的不同用户，而不是您登录的源系统上的shell，在我看来，这将导致源系统用户名用于~.

小开

只需要导出在~/.bashrc中检查非交互式shell时需要的环境变量。

小开

执行remote ssh命令时Shell环境未加载。您可以编辑ssh环境文件:

vi ~/.ssh/environment

其格式为:

VAR1=VALUE1
VAR2=VALUE2

此外，检查sshd配置的PermitUserEnvironment=yes选项。


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