busybox-w32 — BusyBox for Windows, trimmed for AI agents

This project is based on busybox-w32 (the Windows port of BusyBox 1.38). It is positioned as a command-line tool environment for AI agents, and has been trimmed of Linux-exclusive capabilities (kernel modules, init/boot, SELinux, mount/partitioning, network configuration, /proc-based process tools, login/user management, daemon frameworks, etc.), keeping the cross-platform toolset plus the Windows platform layer (win32/ + include/mingw.h).

One source tree, two target platforms:

• Windows (primary target, the agent runtime): make CROSS_COMPILE=x86_64-w64-mingw32- mingw64_defconfig cross-compiles busybox.exe
• Linux/POSIX (development and verification environment): make defconfig builds the cross-platform subset

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Building (cross-compile on Linux)

./build.sh          # build both Linux and Windows x86_64 versions
./build.sh linux    # Linux only
./build.sh win64    # Windows only

Outputs: build-linux/busybox (ELF, ~590 KB, 194 applets), build-win64/busybox.exe (PE32+, ~712 KB, 179 applets). Smoke-test the Windows build with wine: WINEDEBUG=-all wine build-win64/busybox.exe --list.

Manual steps:

make mrproper                    # O= out-of-tree builds require a clean source tree
mkdir -p build-linux && make O=build-linux defconfig && make O=build-linux -j$(nproc)
mkdir -p build-win64 && make O=build-win64 mingw64_defconfig && make O=build-win64 CROSS_COMPILE=x86_64-w64-mingw32- -j$(nproc)

Other configurations in configs/: mingw32_defconfig (32-bit), mingw32w_defconfig (32-bit UTF-8), mingw64u_defconfig (64-bit UTF-8), mingw64a_defconfig.

The default x86_64 Windows profile is deliberately headless: it omits PE icons/version resources and the optional per-file metadata lookups. This keeps the agent binary smaller and avoids extra Windows metadata calls on common file operations without changing its applet set.

Usage

One binary, many commands:

busybox.exe ls -la          # invoke an applet directly
busybox.exe --list          # list all built-in applets
cp a b                      # or name a link/copy after the applet and call it directly

The built-in ash-compatible shell (aliased as sh/bash) supports pipes, redirection, wildcards and job control; built-in applets are called directly from the shell (standalone mode), no PATH install needed.

Windows path notes: always use forward slashes (c:/path, //host/share/path); users, groups and permissions are emulated; device-file emulation provides /dev/null, /dev/tty, /dev/zero, /dev/urandom.

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Applet reference (grouped by function)

Names in parentheses are aliases. ★ marks Windows-specific applets or features enabled only in the Windows build.

Shell & command environment

Applet	Purpose
ash (sh/bash/lash)	Bourne-compatible shell: pipes, redirection, job control, history, line editing
hush (sh)	Smaller shell implementation with lower resource use; drop-in alternative to ash
busybox	Multi-call dispatcher: busybox <applet> <args> or busybox --list

Files & directories

Applet	Purpose
ls (dir)	List directory contents (color, sorting, timestamps, recursion)
cp	Copy files/directories (-r, -a, -p, -i, -l, -s, -u)
mv	Move/rename
rm	Remove files/directories (-r recursive, -f force, -i interactive)
rmdir	Remove empty directories
mkdir	Create directories (-p parents)
touch	Update timestamps or create empty files
ln / link	Create hard/symbolic links
unlink	Remove a single file
install	Copy files with permissions/owner set (used by install scripts)
chmod	Change permissions
chown / chgrp	Change owner/group (emulated on Windows)
chattr / lsattr	Change/show extended attributes (read-only, system, hidden flags on Windows)
stat	Detailed file status (size, permissions, timestamps, inode, ...)
readlink / realpath	Resolve symlink target / print canonical absolute path
basename / dirname	Strip directory part / strip filename part of a path
mktemp	Create a temporary file/dir and print its path
truncate	Shrink/extend a file to a given size
dd	Block-level copy and conversion (offset, block size, ...)
shred	Overwrite file contents for secure deletion
fsync / sync	Flush file / all buffers to disk
flock	Run a command while holding a file lock
chroot	Run a command with a different root directory (Linux only)
mkfifo / mknod	Create named pipes / device nodes (Linux only)
nice / nohup	Run with adjusted priority / immune to hangup
pwd	Print current working directory

Text viewing & processing

Applet	Purpose
cat	Concatenate and print files
tac	Print lines in reverse order
tee	Write to stdout and files simultaneously
head / tail	First / last lines of a file (-f follow)
wc	Count lines, words, bytes
cut	Extract columns by field/byte/char
tr	Character translation/deletion
sort	Sort lines (-n numeric, -r reverse, -k key, -u unique)
uniq	Drop adjacent duplicate lines
comm	Compare two sorted files line by line
join	Join two files on a common field
paste	Merge lines of multiple files
nl	Number lines
fold / expand / unexpand	Wrap lines / convert tabs and spaces
od / hexdump / hd / xxd	Hex dumps (binary analysis)
strings	Extract printable strings from binaries
split	Split files by size/lines
find	Find files by name/type/time/size conditions
xargs	Build and run commands from stdin arguments
sed	Stream editor: search/replace, filtering, scripted transforms
awk	Text-processing language: field parsing, statistics, reports
grep (egrep/fgrep)	Search by regex / extended regex / fixed strings
diff / cmp	Line-by-line / byte-by-byte file comparison
patch	Apply diff patches
ed	Classic line editor
vi	Full-screen editor (search, replace, undo, multiple files)
less / more	Pagers (less supports backward scroll and search)

Encoding, checksums & conversion

Applet	Purpose
base32 / base64	Base32/Base64 encode/decode
uuencode / uudecode	UUencode/decode
md5sum / sha1sum / sha256sum / sha384sum / sha512sum / sha3sum	Hash checksums
cksum / crc32 / sum	POSIX checksum / CRC32 / BSD sum
dos2unix / unix2dos	Line-ending conversion
iconv	Charset conversion

Archives & compression

Applet	Purpose
tar	Archive/create/extract (auto-detects compression)
cpio	cpio archives (initramfs, etc.)
ar	Static library / archive maintenance
gzip/gunzip (zcat)	gzip compression/decompression
bzip2/bunzip2 (bzcat)	bzip2 compression/decompression
xz/unxz (xzcat)	xz compression/decompression
lzma/unlzma (lzcat), lzop/unlzop (lzopcat)	Other LZ-family codecs
uncompress	Legacy .Z decompression
unzip	ZIP extraction (common compression algorithms)
dpkg / dpkg-deb	Debian package (.deb) query/extract
rpm / rpm2cpio	RPM package query / convert to cpio stream

Processes & system

Applet	Purpose
ps (minips)	List processes (task snapshot on Windows)
kill	Terminate a process by PID
killall	Terminate processes by name
killall5	Terminate all processes except self (Linux only)
pgrep / pkill	Match processes by name/attribute: find / signal
pidof	Find PIDs by name
uptime	System uptime and load
free	Memory usage (system info on Windows)
watch	Run a command periodically and refresh output
time	Measure command execution time
nproc	Number of CPU cores
uname (arch)	System/kernel information
hostname / dnsdomainname	Host name / DNS domain
id / groups / whoami / logname	Current user identity (emulated on Windows)
tty / ttysize	Terminal device name / terminal size
date / cal	Date and time (formatting, setting) / calendar
rdate	Set time from a remote time server
df / du	Disk free space / directory usage
who / users / w	Logged-in users / sessions and load
hostid	Host ID (Linux only)

Networking

Applet	Purpose
wget	HTTP/HTTPS/FTP downloader (resume, auth, HTTPS)
nc (netcat)	TCP/UDP swiss army knife: port tests, simple server/client, data transfer
telnet	Interactive Telnet client
tftp / tftpd	TFTP client / simple TFTP server
ftpget / ftpput	Scriptable (non-interactive) FTP download/upload
httpd ★	Embedded HTTP server (static files, CGI, auth, gzip)
nslookup	DNS queries
whois	WHOIS domain/IP lookup
ipcalc	IP/subnet calculator (mask, network, broadcast)
pscan	Simple port scanner
ssl_client	Raw TLS/SSL connection (used by the built-in TLS implementation)

Math & logic

Applet	Purpose
bc / dc	Arbitrary-precision calculator (interactive/script) / RPN calculator
expr	Evaluate expressions (arithmetic, strings, comparison)
factor	Prime factorization
seq	Generate arithmetic sequences
printf	Formatted output
echo	Print text (-e escapes, -n no newline)
test ([)	Condition tests (files, strings, numbers)
true / false	Always succeed / always fail
yes	Print a string repeatedly
sleep / usleep	Sleep for seconds / microseconds
timeout	Run a command with a time limit
shuf	Shuffle input lines randomly
tsort	Topological sort

Environment & shell helpers

Applet	Purpose
env	Show/set environment and run a command
printenv	Print environment variables
export/set/unset/cd etc.	Shell builtins (see ash)
getopt	Parse command-line options (for scripts)
which	Locate an executable in PATH
run-parts	Run all scripts in a directory in order
pipe_progress	Progress display for pipes (used internally)
make (pdpmake)	Built-in make (POSIX compatible)
man	View manual pages

Development & debugging helpers

Applet	Purpose
xxd/hexdump/od	Hex dumps (see Text processing)
hexedit	Interactive hex editor
strings	Extract printable strings from binaries
stty	Set terminal parameters
clear / reset	Clear screen / reset terminal
resize	Print shell command to resize the terminal
script / scriptreplay	Record terminal sessions / replay (reproducibility and auditing)
uuidgen	Generate UUIDs
rev	Reverse characters of each line
tree	Display directory tree
ascii ★	Display the ASCII table
bbconfig	Print the current build configuration
jn	JSON data processing tool
ts	Timestamp tool
inotifyd	File-system event monitoring (Windows notifications)
crond / crontab	Cron daemon / schedule table management
chat	Serial scripted conversation (dial-up, etc.)
microcom	Simple serial terminal
rx	XMODEM receiver

Windows-specific

Applet	Purpose
su (suw32) ★	Run a shell or command with administrator privileges (ShellExecute elevation; -c command, -t test mode)
drop / cdrop / pdrop ★	Lower the process token and run a child with normal privileges
chattr / lsattr	Windows file flags (read-only/system/hidden)

Testing & internal

Applet	Purpose
unit	Unit-test framework entry (disabled by default)
parse	Config-parsing debug tool (disabled by default)

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Design notes & hints

• Standalone shell: built-in applets are called directly from the shell, no PATH needed; set BB_OVERRIDE_APPLETS (space-separated applet names) to force the use of external programs
• Terminal modes: the best terminal handling is auto-detected; BB_TERMINAL_MODE=1 forces literal ANSI escapes, BB_TERMINAL_MODE=0 forces Windows console API emulation
• UTF-8 child processes (UTF-8 builds, FEATURE_UTF8_CONSOLE): at startup the console codepages are switched to UTF-8 (65001, restored at exit) and PYTHONIOENCODING=utf-8 / PYTHONUTF8=1 are set if unset, so output of Python / PowerShell / cmd children stays UTF-8 and matches BusyBox's internal encoding (no more mojibake with mixed encodings). Set BB_SKIP_UTF8_CONSOLE to keep the console codepage unchanged; programs which still emit legacy encodings (e.g. GBK) can be piped through busybox iconv -f CP936 -t UTF-8
• Device-file emulation: /dev/null, /dev/tty, /dev/zero, /dev/urandom work in redirections and as arguments
• Paths: always use forward slashes; UNC paths //host/share/path; the -X shell option prevents conversion of backslashes to forward slashes
• Performance: adding the busybox process to Windows Security exclusions improves performance significantly
• System requirements: Windows 7+ / Server 2008 R2+ (UTF-8 variants require Windows 10+)

More information

• Full applet list and options: busybox.exe --list, busybox.exe <applet> --help
• Development and maintenance notes: AGENTS.md (platform-layer architecture, conventions for adding/removing applets and the ripple-effect checklist)