How to execute a remote command over ssh? - ssh

Question

I try to connect to the remote server by ssh and execute the command.
But given the situation, I can only execute a single command.
For example
ssh -i ~/auth/aws.pem ubuntu#server "echo 1"
It works very well, but I have a problem with the following
case1
ssh -i ~/auth/aws.pem ubuntu#server "cd /"
ssh -i ~/auth/aws.pem ubuntu#server "ls"
case2
ssh -i ~/auth/aws.pem ubuntu#server "export a=1"
ssh -i ~/auth/aws.pem ubuntu#server "echo $a"
The session is not maintained.
Of course, you can use "cd /; ls"
but I can only execute one command at a time.
...
Reflecting comments
developed a bash script
function cmd()
{
local command_delete="$#"
if [ -f /tmp/variables.current ]; then
set -a
source /tmp/variables.current
set +a
cd $PWD
fi
if [ ! -f /tmp/variables.before ]; then
comm -3 <(declare | sort) <(declare -f | sort) > /tmp/variables.before
fi
echo $command_delete > /tmp/export_command.sh
source /tmp/export_command.sh
comm -3 <(declare | sort) <(declare -f | sort) > /tmp/variables.after
diff /tmp/variables.before /tmp/variables.after \
| sed -ne 's/^> //p' \
| sed '/^OLDPWD/ d' \
| sed '/^PWD/ d' \
| sed '/^_/ d' \
| sed '/^PPID/ d' \
| sed '/^BASH/ d' \
| sed '/^SSH/ d' \
| sed '/^SHELLOPTS/ d' \
| sed '/^XDG_SESSION_ID/ d' \
| sed '/^FUNCNAME/ d' \
| sed '/^command_delete/ d' \
> /tmp/variables.current
echo "PWD=$(pwd)" >> /tmp/variables.current
}
ssh -i ~/auth/aws.pem ubuntu#server "cmd cd /"
ssh -i ~/auth/aws.pem ubuntu#server "cmd ls"
What better solution?

Answer 1

$ cat <<'EOF' | ssh user#server
export a=1
echo "${a}"
EOF
Pseudo-terminal will not be allocated because stdin is not a terminal.
user#server's password:
1
In this way you will send all commands to ssh as a single file script, so you can put any number of commands. Please note the way to use EOF between single quote '.