This example shows how write a pipeline made up of two simple BASH processes, so that the results produced by the first are consumed by the second process.
Line 1: The script starts with a shebang declaration. This allows you to launch your pipeline, as any other BASH script.
Line 3: Declares a pipeline parameter named params.in that is initialized with the value $HOME/sample.fa.This value can be overridden when launching the pipeline, by simply adding the option --in <value> to the script command line.
Lines 8-20: The process that splits the provided file.
Line 10: Opens the input declaration block. The lines following this clause are interpreted as input definitions.
Line 11: Declares the process input file. This file is taken from the params.in parameter and named input.fa.
Line 13: Opens the output declaration block. Lines following this clause are interpreted as output declarations.
Line 14: Defines that the process outputs files whose names match the pattern seq_*. These files are sent over the channel records.
Lines 16-18: The actual script executed by the process to split the provided file.
Lines 24-35: Defines the second process, that receives the splits produced by the previous process and reverses their content.
Line 26: Opens the input declaration block. Lines following this clause are interpreted as input declarations.
Line 27: Defines the process input file. This file is received through the channel records.
Line 29: Opens the output declaration block. Lines following this clause are interpreted as output declarations.
Line 30: The standard output of the executed script is declared as the process output. This output is sent over the channel result.
Lines 32-34: The actual script executed by the process to reverse the content of the received files.
Line 40: Prints a result each time a new item is received on the result channel.