std.os#

The machine and the process a program runs in: environment variables, the working directory, the home directory, and which platform this is.

mars

takepkg std.os;

func m{
    out(os.platform(), os.arch());          // windows x86_64
    editor = os.env_or("EDITOR", "nano");
    out("editing with", editor, "in", os.cwd());
}

Function or value	Result
`env(name)`	The value of an environment variable, or `null` when it is not set
`env_or(name, fallback)`	The value, or `fallback` when it is not set
`environment()`	Every environment variable, as a map sorted by name
`cwd()`	The working directory, which relative paths are read from
`home()`	The user's home directory, or `null` when the environment does not say
`platform()`	`"windows"`, `"linux"`, or `"macos"`, otherwise the name Rust gives it
`arch()`	The processor architecture, such as `"x86_64"` or `"aarch64"`
`pid()`	The process ID of the running program
`SEP`	The path separator: `"\\"` on Windows, `"/"` elsewhere

Environment variable names are case-sensitive, except on Windows, where Path and PATH are one variable. env follows the platform's rule, and on Windows environment() spells every name in upper case, as Python's os.environ does, so os.environment().get("PATH") works everywhere. A name that is empty or contains = raises RangeError. A value that is not valid Unicode is read with replacement characters rather than raising.

std.os reads the environment and does not change it. Files and directories belong to std.file. The program's own arguments and exit status are std.cli, and the interpreter running it is std.sys.

The wrapper is written in Marslang (std/os.mars) over the native package std/rs/os.rs.