pipeline processing using cat original: ./A_process.py _ < input.dict > output.dict.tmp ./B_process.py _ < output.dict.tmp > output.dict rm output.dict.tmp I am trying to make it into a pipeline, so cat input.dict | A_process.py _ | B_process.py _ > output.dict however it shows "A_process.py command not found"... I guess something wrong with the environment, but not sure what to do.

As @steeldriver wrote in his comment, the problem you are facing is that the script you are executing is not in your `PATH`

The simple solution will be to add the prefix `./` to the script-name, assuming that you are running the command in the same folder the script is located:


cat input.dict | ./A_process.py _ | ./B_process.py _ > output.dict


Other options might be:

* Add the path of the script location into the `PATH` variable.
* Instead of `./script_name` use full-path of the script `/full/path/to/script/directory/A_process.py`