How to define inputs to a task
Some tasks will require inputs such as the name of servers, paths to files, or credentials.
xc tasks are executed as shell scripts, so they support shell syntax for variables.
xc [task-name] [inputs...]
Syntax - Named Inputs
The Inputs attribute can be used to denote required parameters, which at runtime will be converted to environment variables.
## Tasks
### greet
Inputs: FORENAME, SURNAME
```
echo "Hello, $FORENAME $SURNAME."
```
Named Inputs can be passed via command arguments:
$ xc greet Joe Bloggs
+ echo 'Hello, Joe Bloggs.'
Hello, Joe Bloggs.
Or via environment variables:
$ export FORENAME=Joe
$ export SURNAME=Bloggs
$ xc greet
+ echo 'Hello, Joe Bloggs.'
Hello, Joe Bloggs.
xc will return an error if Inputs are not passed:
$ xc greet
Task has required inputs:
xc greet <forename> <surname>
FORENAME=<forename> SURNAME=<surname> xc greet
exit status 1
Syntax - Optional Inputs
Combining the Environment attribute and the Inputs attribute, you can create optional inputs to a task.
## Tasks
### greet
Inputs: NAME
Environment: NAME=World
```
echo "Hello, $NAME."
```
Can be ran as:
$ xc greet Joe
+ echo 'Hello, Joe.'
Hello, Joe.
or
$ xc greet
+ echo 'Hello, World.'
Hello, World.
Syntax - Positional
As xc tasks are executed as shell scripts you can also use positional syntax of arguments.
(xc will not return an error if a script uses positional syntax and the input is not provided)
## Tasks
### greet
```
echo "Hello, $1."
```
Can be ran as:
$ xc greet Joe
+ echo 'Hello, Joe.'
Hello, Joe.
Syntax - Variadic
As xc tasks are executed as shell scripts you can also use variadic syntax of arguments.
(xc will not return an error if a script uses variadic syntax and no inputs are provided)
## Tasks
### greet-everyone
```
echo "Hello, $@."
```
Can be ran as:
$ xc greet Joe Bob Steve
+ echo 'Hello, Joe Bob Steve.'
Hello, Joe Bob Steve.