Toybox: all-in-one Linux command line. --- Getting started You can download static binaries for various targets from: http://landley.net/toybox/bin The special name "." indicates the current directory (just like ".." means the parent directory), and you can run a program that isn't in the $PATH by specifying a path to it, so this should work: wget http://landley.net/bin/toybox-x86_64 chmod +x toybox-x86_64 ./toybox-x86_64 echo hello world --- Building toybox Type "make help" for build instructions. Usually you want something like: make defconfig LDFLAGS="--static" CROSS_COMPILE=armv5l- make toybox PREFIX=/path/to/root/filesystem make install The CROSS_COMPILE argument is optional, and without it builds a version of toybox to run on the current machine. Cross compiling requires an appropriately prefixed cross compiler toolchain, several example toolchains are available at: http;//landley.net/aboriginal/bin For the "CROSS_COMPILE=armv5l-" example above, download cross-compiler-armv5l.tar.bz2, extract it, and add its "bin" subdirectory to your $PATH. (And yes, the trailing - is significant, because the prefix includes a dash.) For more about cross compiling, see: http://landley.net/writing/docs/cross-compiling.html http://landley.net/aboriginal/architectures.html --- Using toybox The toybox build produces a multicall binary, a "swiss-army-knife" program that acts differently depending on the name it was called by (cp, mv, cat...). Installing toybox adds symlinks for each command name to the $PATH. The special "toybox" command treats its first argument as the command to run. With no arguments, it lists available commands. This allows you to use toybox without installing it. This is the only command that can have an arbitrary suffix (hence "toybox-armv5l"). The "help" command provides information about each command (ala "help cat"). --- Configuring toybox It works like the Linux kernel: allnoconfig, defconfig, and menuconfig edit a ".config" file that selects which features to include in the resulting binary. The maximum sane configuration is "make defconfig": allyesconfig isn't recommended for toybox because it enables unfinished commands and debug code. --- Creating a Toybox-based Linux system Toybox is not a complete operating system, it's a program that runs under an operating system. Booting a simple system to a shell prompt requires three packages: an operating system kernel (Linux) to drive the hardware, a program for the system to run (toybox), and a C library to tie them together (toybox has been tested with musl, uClibc, glibc, and bionic). The C library is part of a "toolchain", which is an integrated suite of compiler, assembler, and linker, plus the standard headers and libraries necessary to build C programs. Static linking (with the --static option) copies the shared library contents into the program, resulting in larger but more portable programs, which can run even if they're the only file in the filesystem. Otherwise, the "dynamically" linked programs require the library files to be present on the target system ("man ldd" and "man ld.so" for details). An example toybox-based system is Aboriginal Linux: http://landley.net/aboriginal/about.html That's designed to run under qemu, emulating several different hardware architectures (x86, x86-64, arm, mips, sparc, powerpc, sh4). Each toybox release is regression tested by building Linux From Scratch under this toybox-based system on each supported architecture, using QEMU to emulate big and little endian systems with different word size and alignment requirements. --- Presentations 1) "Why Toybox?" 2013 talk here at CELF video: http://youtu.be/SGmtP5Lg_t0 outline: http://landley.net/talks/celf-2013.txt linked from http://landley.net/toybox/ in nav bar on left as "Why is it?" - march 21, 2013 entry has section links. 2) "Why Public Domain?" The rise and fall of copyleft, Ohio LinuxFest 2013 audio: https://archive.org/download/OhioLinuxfest2013/24-Rob_Landley-The_Rise_and_Fall_of_Copyleft.mp3 outline: http://landley.net/talks/ohio-2013.txt 3) Why did I do Aboriginal Linux (which led me here) 260 slide presentation: https://speakerdeck.com/landley/developing-for-non-x86-targets-using-qemu How and why to make android self-hosting: http://landley.net/aboriginal/about.html#selfhost 4) What's new with toybox (ELC 2015 status update): video: http://elinux.org/ELC_2015_Presentations outline: http://landley.net/talks/celf-2015.txt