无法通过 ssh 隧道在远程主机上执行嵌套命令

双引号字符串仍将允许本地 bash shell 扩展变量、命令替换……在字符串内。

这意味着您的命令将docker ps --format '{{.Names}}' | grep '^backend'在本地机器上执行，而不是像您希望的那样在远程机器上执行。

ssh ${REMOTE_HOST} "docker restart $(docker ps --format '{{.Names}}' | grep '^backend')"

您可以尝试使用以下方法转义它：

ssh ${REMOTE_HOST} "docker restart \$(docker ps --format '{{.Names}}' | grep '^backend')"

或者使用单引号。这是一个例子：

ssh ${REMOTE_HOST} 'docker restart $(docker ps --format {{.Names}} | grep ^backend)'

更多详细信息，您可以在引用部分找到 bash (1)手册页。

   There are three quoting mechanisms: the escape character, single
   quotes, and double quotes.

   A non-quoted backslash (\) is the escape character.  It preserves
   the literal value of the next character that follows, with the
   exception of <newline>.  If a \<newline> pair appears, and the
   backslash is not itself quoted, the \<newline> is treated as a
   line continuation (that is, it is removed from the input stream
   and effectively ignored).

   Enclosing characters in single quotes preserves the literal value
   of each character within the quotes.  A single quote may not
   occur between single quotes, even when preceded by a backslash.

   Enclosing characters in double quotes preserves the literal value
   of all characters within the quotes, with the exception of $, `,
   \, and, when history expansion is enabled, !.  When the shell is
   in posix mode, the ! has no special meaning within double quotes,
   even when history expansion is enabled.  The characters $ and `
   retain their special meaning within double quotes.  The backslash
   retains its special meaning only when followed by one of the
   following characters: $, `, ", \, or <newline>.  A double quote
   may be quoted within double quotes by preceding it with a
   backslash.  If enabled, history expansion will be performed
   unless an !  appearing in double quotes is escaped using a
   backslash.  The backslash preceding the !  is not removed.