Example:
#!/bin/bash
source "$VARIABLE"
Is to retrieve values from a remote location using curl.
http://example.com/file.cnfg
2 Answers
Executing downloads blindly is definitely not something you want to do casually.
You can execute the contents of a variable using eval, as in:
eval "$variable"
That's not something you want to do without thinking through the security implications either.
2 Comments
Robin pilot
I am beginner in bash, so I am a bit blindly. But if the request is to my own server, you also need to consider security issues?
rici
@RobinPlotnik: Security is not just about malicious attacks. Suppose your server returns an error instead of the data you expect, and your code executes the error as though it were a shell script. How sure are you that the random content of the error does not contain something which could do damage? HTML contains lots of >, for example. How possible is it that the next word happens to name a file?
You don't need or want a variable. The common way to do this is
curl http://example.com/file.cnfg | sh
If you really genuinely need to execute the code in the current shell,
source <(curl http://example.com/file.cnfg)
does that.
Caveats about security implications cannot be overstated. You need to understand what could go wrong if the server is malicious, hijacked, misconfigured, down, or just in a really grumpy mood.
You should be asking yourself "can I avoid using a variable" (and also, "can I avoid spawning an external process") and if the answer is yes, that's usually what you should do.
VARIABLE="curl 'http://example.com/file.cnfg'"and this is what you want to evaluate. As an aside (and as implied in rici's answer) you should not use upper case for your private variables; uppercase is reserved for system variables.