So I have this curl command. But I want to store the API-key in a file called api.txt and have it load where the value is in the curl command.

api.txt files contains

```
'X-Api:<API-KEY>'

```

This command works.

```
curl -H 'X-Api:<API-KEY>' -T file.zip "https://URL"

```

Tried:

```
curl -H “Content-Type: text/plain” -d “api.txt” -T file.zip "https://URL"

```

Got error:

```
  "errors" : [ {
    "status" : 401,
    "message" : "Unauthorized"
  } ]
}%      

```

Question:

1. How can I load either the actual api key or the expected line from api.txt to parse it into the curl command?
2. is this the way to do this? or a better way?