KDAriane

h1. Eval201

h2. Synopsis

This operator has two parameters and no input. The corresponding shell script executes the two parameters as a command, and copies the result in the output.

It is useful for commands with arguments, such as @awk@ commands whose arguments include space, quotes, etc., that could not be written with only one parameter in [[eval101]]. It can also produce file with commands using the parameters given by Ariane.

h2. Parameters

2 parameters, treated as the command to be executed.

h2. Inputs

No input

h2. Outputs

1 output: the result of the command

h2. Shell code

<pre>

cmd=$1; shift

args=$1; shift

output=$1; shift

$cmd $args > $output

</pre>

h2. Example

This operator can be used for generating a file with an @awk@ instruction, for example:

<pre>

awk '{for(i=1;i<=10;i++)printf("train.%d", i)} input > output

</pre>

See the scenario [[perturbation.aws]], where this operator uses @echo@ for saving a parameter in a file.