How to execute a Bash alias over ssh

Question

Here's what I'm trying to do:

ssh andy@<ip_address> "cat .bash_aliases; sayhello"

Here's what happens:

alias sayhello="echo hello"
bash: sayhello: command not found

---

To be more specific about my problem I'm trying to invoke the command
"sudo etherwake -i eth0 <mac_address>" over ssh -- this executes (I think) on my local computer, giving a sudo: unable to resolve host [blabla] error. It seems like any commands that are not standard bash commands are parsed by my local machine.

If that's what's happening, how do I get around it? If not, what is the explanation?

Answer 1

In general this is not a good idea to use aliases in scripts.

Yet I can suggest one way to do it, but bare in mind how unsafe it is.

• It relies on eval,
• It reads remote files into the shell context.

Here we go.

ssh remote_host "shopt -s expand_aliases ; source ~/.bash_aliases ; eval sayhello"

Explanation:

1. By default alias expansion is enabled only for interactive shells. To turn it on use shopt -s command.

2. You will need to source the aliases into your shell context anyway.

3. Now you are set to use your aliases via the eval command.