The leading contender for a multi-function program that could be used instead of busybox is toybox.
The Toybox material previously on this page has been moved to http://landley.net/toybox/roadmap.html
Sony CE Linux (internal distribution) 1.13.4 build
This is from a version of busybox used in lots of Sony products: Currently defined functions:
[, [[, ash, basename, bunzip2, bzcat, cat, chgrp, chmod, chown, chroot, cmp, cp, cpio, cut, date, dd, dirname, dmesg, echo, egrep, env, expr, false, fgrep, freeramdisk, ftpget, ftpput, getty, grep, gunzip, gzip, halt, ifconfig, insmod, kill, killall, klogd, ln, logger, login, ls, lsmod, md5sum, mkdir, mkfifo, mknod, mktemp, modprobe, mount, mv, pidof, ping, ping6, pivot_root, poweroff, pwd, readlink, reboot, rm, rmdir, rmmod, route, sed, sfdisk, sh, sha1sum, sleep, sort, stty, swapoff, swapon, switch_root, sync, syslogd, tail, tar, taskset, telnet, telnetd, test, touch, true, umount, uname, uniq, usleep, vconfig, wc, xargs, zcat
The following is Tim's prioritization of the above list, based on his own experience with embedded systems. I will divide the above list into 3 groups: must-have, nice-to-have, not-that-important.
cat chgrp chmod chown cp date df echo env expr false find grep head id kill ln ls mkdir more mv nice ps pwd rm rmdir sh sleep sort tail test touch true uname uniq wc xargs
(must have, not in the above list: chroot, dmesg, sync)
basename cut dd diff dirname du mkfifo printf sed tee time vi who zcat
at awk bc cal cksum cmp comm csplit expand file fold fuser getconf link logger logname man newgrp nl nohup od paste patch pathchk renice split stty tabs tput tr tty unexpand unlink uudecode uuencode
Must-have unimplemented: The following list has Tim's must-have commands, which are currently (as of Jan, 2012) not implemented in toybox:
chgrp chmod chown date dd expr find grep head id kill ln ls mkdir more mv nice ps rm tail test touch uniq xargs
prioritized, must-have, unimplemented list
Prioritized top 13:
1. ls 2. mkdir 3. rm 4. ln 5. mv 6. ps 7. kill 8. chmod 9. chown 10. date 11. grep 12. find 13. xargs
Second prioritized group:
chgrp id nice expr head tail test touch uniq dd more
IMHO - ls needs to support -ladR at first
If we omit toolbox supported commands from the must-have, unimplemented list, we get:
chgrp expr false find grep head more nice tail test touch true uname xargs
I would add tab completion and globbing for toysh to the list.
This would be for a toolbox complement.
Other multi-tool programs
Beastiebox currently implements
Here’s a link to the Beastiebox project: http://beastiebox.sourceforge.net/ which has been proven to be capable to replace busybox, in general. It mostly consists of BSD sources and contains, according to the homepage:
[ cat chmod cp date df disklabel dmesg ex fdisk fsck fsck_ffs getty halt hostname ifconfig init kill less ln login ls mksh more mount mount_ffs mv pfctl ping poweroff ps reboot rm route sed sh stty sysctl tar test traceroute umount vi wiconfig
Of course, every command is optional; for example, pfctl is currently BSD specific, and fsck_ffs/mount_ffs do not make much sense on Linux either, so these would be disabled in a Linux build of Beastiebox.
On the TODO side, the Linux specific commands would need to be implemented or taken from one of the others (Toybox, Android Toolbox, etc).
It does contain a complete shell (mksh, MirBSD Korn Shell) under a BSD-ish licence, which can be used as /bin/sh (e.g. on Debian) and is the default /system/bin/sh on Android ICS and later, even. This is not much bigger than the sh included with Busybox, Beastiebox (can be disabled in favour of mksh) and others, but has functions such as command line editing, UTF-8 support, Tab completion, Korn Shell scripting features ([[, arrays, etc). and is actively developed on its own.
Can implement incrementally
One nice thing about busybox/toolbox is you can install multiple implementations side by side, and have what symlinks you create (or what comes first in the $PATH) determine who is implementing what.
This allows gradual transitions. Each release, we replace a couple more commands from the old one, until the old one finally isn't being used for anything anymore and we can uninstall it...