Easily invoke commands from one directory (CommandPath)

A CommandPath is an object that you can create to represent a directory with executables in it. You can then use that object to get command objects which you can then run.

This feature was created to be able to create a “postgres” or “node” or “virtualenv” CommandPath object referencing their bin directory. Commands in those bin directories (e.g. postgres / psql) could be run and be able to directly call other commands in that directory without referencing the absolute path.

Command objects that are created from CommandPath objects will automatically be run with that directory added to the beginning of their PATH. This means that they can run each other directly without specifying the directory.

bin_directory/ls:

#!/bin/bash
echo hello $1 > output

bin_directory/command1:

#!/bin/bash
ls $1

bin_directory/command2:

#!/bin/bash
echo hello $1 > output

bin_directory/command_calling_command_in_path:

#!/bin/bash
command1 tom

bin_directory/command.with.dots:

#!/bin/bash
echo hello dots > output
from commandlib import CommandPath

command_path = CommandPath("./bin_directory")

Run command from CommandPath:

command_path.command1("harry").run()

File ‘output’ will contain:

hello harry

Command can call other command in CommandPath without specifying its path:

command_path.command_calling_command_in_path("tom").run()

File ‘output’ will contain:

hello tom

Commands with dots in command path are translated into underscores:

command_path.command_with_dots("tom").run()

File ‘output’ will contain:

hello dots

Referencing a non-existent command raises an exception:

command_path.non_existent_command
commandlib.exceptions.CommandError:
'non_existent_command' not found in '/path/to/bin_directory'