Standard library

nox.os

Process-level information and control: command-line arguments, environment variables, the working directory and exit.

Text

import nox.os
from nox.os import OsError

Capability: process.

Functions#

Function	Description
`arg_count()`	the number of command-line arguments, including the program name at index 0
`arg(i)`	argument `i` as a `str`
`getenv(name)`	the value of an environment variable; raises `OsError` if it is not set
`set_var(name, value)`	sets an environment variable for this process and its children
`current_dir()`	the current working directory
`exit(code)`	terminates the program immediately with exit status `code`

Arguments given to noxc run file.nox -- a b c (or to a compiled program) appear as arg(1), arg(2), arg(3).

Nox

import nox.os
from nox.os import OsError

print(nox.os.arg_count() >= 1, nox.os.getenv("HOME") != "")
try:
    nox.os.getenv("NOX_SURELY_UNSET_VAR")
except OsError as e:
    print("not set")
nox.os.set_var("NOX_DEMO", "42")
print(nox.os.getenv("NOX_DEMO"), nox.os.current_dir() != "")

Output

True True
not set
42 True

Notes#

exit ends the process without running finally blocks or defers that are still pending — flush and close what you need first. A normal return from the top level exits with status 0, an uncaught exception with status 1.
getenv has no default-value form; test for absence with try/except OsError.
Environment changes made with set_var are visible to child processes started with nox.process.

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