Cross-Platform Support

Tested Environments

Environment	Build Target	Shell	HOME	Status
macOS arm64	native	/bin/sh (zsh)	always set	Tested
macOS x86_64	native	/bin/sh (zsh)	always set	Tested
Ubuntu 22.04	x86_64-unknown-linux-gnu	/bin/sh (dash)	usually set	Tested
Ubuntu 24.04	x86_64-unknown-linux-gnu	/bin/sh (dash)	usually set	Tested
Alpine 3.x	x86_64-unknown-linux-musl	/bin/sh (busybox ash)	usually set	Tested
LXC container	matches host	varies	often missing	/etc/passwd fallback
Proxmox VE host	x86_64-unknown-linux-gnu	/bin/sh (dash)	set	Tested
systemd service	matches host	varies	often missing	/etc/passwd fallback
cron job	matches host	varies	often missing	/etc/passwd fallback
Windows 10/11	x86_64-pc-windows-msvc	none (direct spawn)	%LOCALAPPDATA%	Experimental (CI smoke-tested)

Windows (experimental)

On Windows the command is spawned directly via CreateProcess — no shell. stdout and stderr are merged by two drain threads feeding one channel, so interleaving between the two streams is best-effort (per read chunk) rather than the kernel-exact ordering sh -c '… 2>&1' provides on unix; each stream's own ordering is always preserved. Consequences:

• Shell syntax needs an explicit shell: l0-compressor cmd /C "a | b".
• Ctrl-C follows default console semantics (delivered to the process group); there is no signal forwarding. The --idle-timeout watchdog kills the child tree with taskkill /F /T.
• The data directory resolves to %XDG_DATA_HOME%, then %LOCALAPPDATA%, then %USERPROFILE%\.local\share.
• The 0600/0700 permission hardening and the --recover symlink defenses are unix-only; Windows temp and profile directories are per-user.
• The safety guard's rm -rf matcher already understands C:\Users / /c/Users spellings.

Coverage: the unit suite runs on Windows in CI (the E2E suite is unix-gated), plus a CI smoke test for native spawn, truncation, stderr merge, and exit-code propagation.

Build Targets

macOS (native)

cargo build --release
# produces: target/release/l0-compressor (arm64 or x86_64, depending on host)

Linux glibc (Ubuntu, Debian, RHEL)

cargo build --release --target x86_64-unknown-linux-gnu

Requires a Linux cross-compiler if building from macOS. The Makefile handles this automatically.

Linux musl (Alpine, containers)

CC_x86_64_unknown_linux_musl=x86_64-linux-musl-gcc \
cargo build --release --target x86_64-unknown-linux-musl

Produces a fully static binary with no runtime dependencies. This is the recommended build for containers and minimal environments.

Shell Compatibility

The 2>&1 redirect and single-quote escaping used by l0-compressor are POSIX sh compatible. They work identically on:

• dash (Ubuntu default /bin/sh)
• bash (common on RHEL, macOS pre-Catalina)
• zsh (macOS default since Catalina)
• busybox ash (Alpine default /bin/sh)

The only environment where this fails is distroless containers or scratch images that have no shell at all. In that case, use l0-compressor -i for passthrough mode (no 2>&1 merge).

HOME Resolution

l0-compressor resolves the data directory in this order:

1. $XDG_DATA_HOME/l0-compressor/
2. $HOME/.local/share/l0-compressor/
3. /etc/passwd lookup using the current UID

The /etc/passwd fallback handles:

• lxc exec container -- l0-compressor cargo test (no $HOME)
• Cron jobs without HOME= in the crontab
• systemd services without User= (runs as root, $HOME may not be set)