在shell脚本中使用相同的命令，只需使用前缀

I have a command I run to check if a certain db exists.
I want to do it locally and via ssh on a remote server.
The command is as so:

我有一个命令，我检查是否存在某个数据库。我想在本地进行，并通过远程服务器上的ssh进行。命令如下：

mysqlshow -uroot | grep -o $DB_NAME

My question is if I can use the same command for 2 variables,
the only difference being ssh <remote-server> before one?
Something along the lines of !! variable expansion in the CLI:

我的问题是，如果我可以对2个变量使用相同的命令，唯一的区别是ssh 在一个之前？有点像!! CLI中的变量扩展：

LOCAL_DB=mysqlshow -uroot | grep -o $DB_NAME
REMOTE_DB=ssh <remote-host> !!

2 个解决方案

#1

something like this perhaps?

也许这样的事情？

cmd="whoami"
eval $cmd
ssh remote@host $cmd

eval will run the command in the string $cmd locally

eval将在本地字符串$ cmd中运行该命令

also, for checking tables, it's safer to ask for the table name explicitly via a query

另外，对于检查表，通过查询显式地请求表名更安全

SHOW TABLES LIKE 'yourtable';

and for databases:

对于数据库：

SHOW DATABASES LIKE 'yourdb';

#2

You can create a function in .bashrc something like:

您可以在.bashrc中创建一个函数，例如：

function showrdb() {  
   ssh remote@host "$1" 
}  
export -f showrdb

and then source .bashrc and call the function like;

然后源.bashrc并调用函数;

showrdb "command you want to run on remote host"

Or alternately you can create a shell script contains the same function(or only the ssh line) and call the script as

或者，您可以创建一个包含相同功能（或仅包含ssh行）的shell脚本，并将脚本调用为

./scriptname "command to execute of remote host"

But the level of comfort for me is more in first approach.

但对我来说，舒适程度更多的是第一种方法。

#1