Código:
/usr/local/etc # busyboxBusyBox v1.1.3 (2010.04.29-10:11+0000) multi-call binary
Usage: busybox [function] [arguments]...
or: [function] [arguments]...
BusyBox is a multi-call binary that combines many common Unix
utilities into a single executable. Most people will create a
link to busybox for each function they wish to use and BusyBox
will act like whatever it was invoked as!
Currently defined functions:
[, [[, addgroup, adduser, ash, basename, busybox, cat, chmod, chown, chroot, clear, cp, cut, date, dd, delgroup, deluser, devfsd, df,
dirname, dmesg, du, e2fsck, echo, egrep, eject, expr, false, fdisk, fgrep, find, free, fsck, fsck.ext2, fsck.ext3, ftpget, ftpput, getopt,
grep, halt, head, hexdump, hostname, httpd, hwclock, id, ifconfig, inetd, init, insmod, ipcrm, ipcs, kill, killall, klogd, linuxrc,
ln, logger, login, losetup, ls, lsmod, lzmacat, mkdir, mke2fs, mkfs.ext2, mkfs.ext3, mkfs.extk, mknod, mkswap, mktemp, modprobe, more,
mount, mv, netstat, nice, passwd, pidof, ping, pivot_root, poweroff, printf, ps, pwd, readlink, reboot, rm, rmdir, rmmod, route, sed,
sh, sleep, sort, stty, swapoff, swapon, sync, syslogd, tail, tar, tee, telnetd, test, tftp, time, touch, tr, true, tune2fs, udhcpc,
udhcpd, umount, uname, unlzma, unzip, uptime, usleep, vi, wc, wget, which, yes
Lo que he hecho es ejecutar el propio comando busybox y te enseña todo sus comandos internos entre los que está el demonio de telnet telnetd.