How to execute a remote command over ssh with arguments?

Question

In my .bashrc I define a function which I can use on the command line later:

function mycommand() {
    ssh user@123.456.789.0 cd testdir;./test         


        

Answer 1

This is an example that works on the AWS Cloud. The scenario is that some machine that booted from autoscaling needs to perform some action on another server, passing the newly spawned instance DNS via SSH

# Get the public DNS of the current machine (AWS specific)
MY_DNS=`curl -s http://169.254.169.254/latest/meta-data/public-hostname`


ssh \
    -o StrictHostKeyChecking=no \
    -i ~/.ssh/id_rsa \
    user@remotehost.example.com \
<< EOF
cd ~/
echo "Hey I was just SSHed by ${MY_DNS}"
run_other_commands
# Newline is important before final EOF!

EOF

Answer 2

I'm using the following to execute commands on the remote from my local computer:

ssh -i ~/.ssh/$GIT_PRIVKEY user@$IP "bash -s" < localpath/script.sh $arg1 $arg2

Answer 3

Do it this way instead:

function mycommand {
    ssh user@123.456.789.0 "cd testdir;./test.sh \"$1\""
}

You still have to pass the whole command as a single string, yet in that single string you need to have $1 expanded before it is sent to ssh so you need to use "" for it.

Update

Another proper way to do this actually is to use printf %q to properly quote the argument. This would make the argument safe to parse even if it has spaces, single quotes, double quotes, or any other character that may have a special meaning to the shell:

function mycommand {
    printf -v __ %q "$1"
    ssh user@123.456.789.0 "cd testdir;./test.sh $__"
}

• When declaring a function with function, () is not necessary.
• Don't comment back about it just because you're a POSIXist.

Answer 4

Reviving an old thread, but this pretty clean approach was not listed.

function mycommand() {
    ssh user@123.456.789.0 <<+
    cd testdir;./test.sh "$1"
+
}