Can I get the original value if variable empty

[jLopezbarb]

Hi, I need to know if there is a variable in my text that is empty after expanding it. I need those variables not to expand and use the original string.

os.Setenv("GREETINGS", "hello")
value := "$GREETINGS $NAME"
result, err := envsubst.String(value)
if err != nil {
	return "", fmt.Errorf("error expanding environment on '%s': %s", value, err.Error())
}
fmt.Println(result) // The output is: "hello "

Is there a way of getting hello $NAME as the output?

[ashvinsharma]

This would be so helpful.

[artemiyokulov]

need this too!

[hellt]

Did anyone implemented this feature over time? I went looking into the forks, and the closes thing I found is https://github.com/dnitsch/envsubst by @dnitsch

https://github.com/dnitsch/envsubst/blob/86a677a7c7e531f5ce7c9efa9e5c3a888f463446/envsubst.go#L33

The only drawback with this fork is that it doesn't seem to handle the default variables, that is when your template contain a variable that is set to a default when not set in the env:

"if default is set, noreplace should not be used": {
	input: `Some: $REPLACE
NoReplaceNotToBeUsed: ${someVarWithDefault:=myDefault}`,
	env:          []string{"REPLACE=bar"},
	restrictions: &Restrictions{NoUnset: false, NoEmpty: false, NoDigit: true, NoReplace: true},
	expected: `Some: bar
NoReplaceNotToBeUsed: myDefault`,
},

The above test fails in this fork...