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System ​

Environment Variables ​

env ​

Get the value of an environment variable. Returns nil if not set.

scheme
(env "HOME")       ; => "/Users/ada"
(env "PATH")       ; => "/usr/bin:/bin:..."
(env "MISSING")    ; => nil

sys/env-all ​

Return all environment variables as a map.

scheme
(sys/env-all)   ; => {:HOME "/Users/ada" :PATH "..." ...}

sys/set-env ​

Set an environment variable for the current process.

scheme
(sys/set-env "KEY" "value")
(env "KEY")   ; => "value"

System Information ​

sys/args ​

Return the command-line arguments as a list.

scheme
(sys/args)   ; => ("sema" "script.sema" "--flag")

sys/cwd ​

Return the current working directory.

scheme
(sys/cwd)   ; => "/current/dir"

sys/platform ​

Return the platform name.

scheme
(sys/platform)   ; => "macos" / "linux" / "windows"

sys/os ​

Return the operating system name.

scheme
(sys/os)   ; => "macos"

sys/arch ​

Return the CPU architecture.

scheme
(sys/arch)   ; => "aarch64" / "x86_64"

Process Information ​

sys/pid ​

Return the current process ID.

scheme
(sys/pid)   ; => 12345

sys/tty ​

Return the TTY device path, or nil if not running in a terminal.

scheme
(sys/tty)   ; => "/dev/ttys003" or nil

sys/which ​

Find the full path to an executable, or nil if not found.

scheme
(sys/which "cargo")   ; => "/Users/ada/.cargo/bin/cargo"
(sys/which "nonexistent")  ; => nil

sys/elapsed ​

Return nanoseconds elapsed since the process started.

scheme
(sys/elapsed)   ; => 482937100

Session Information ​

sys/interactive? ​

Test if stdin is a TTY (i.e., running interactively).

scheme
(sys/interactive?)   ; => #t in REPL, #f in scripts

sys/hostname ​

Return the system hostname.

scheme
(sys/hostname)   ; => "my-machine"

sys/user ​

Return the current username.

scheme
(sys/user)   ; => "ada"

Directory Paths ​

sys/home-dir ​

Return the user's home directory.

scheme
(sys/home-dir)   ; => "/Users/ada"

sys/temp-dir ​

Return the system temporary directory.

scheme
(sys/temp-dir)   ; => "/tmp"

Shell & Process Control ​

shell ​

Run a shell command and return its stdout as a string.

scheme
(shell "ls -la")       ; => "total 42\n..."
(shell "echo hello")   ; => "hello\n"

exit ​

Exit the process with a given status code.

scheme
(exit 0)   ; exit successfully
(exit 1)   ; exit with error