BusyBox is a version of the GNU utilities designed with embedded Linux (the GP2X is an embedded Linux device) in mind, and therefore has a much smaller space and resource requirement than its larger, more full-featured GNU cousins. Many less important options and commands have been removed from BusyBox to achieve this target. However, BusyBox is still a very complete environment.
The commands offered by BusyBox are various and similar (in most cases exactly the same) in use to the GNU Utils that they replace. A complete list of commands, from the BusyBox command help:
[, [[, addgroup, adduser, adjtimex, ar, arping, ash, awk, basename, bbconfig, bunzip2, busybox, bzcat, cal, cat, catv, chattr, chgrp, chmod, chown, chroot, chvt, cksum, clear, cmp, comm, cp, cpio, crond, crontab, cut, date, dc, dd, deallocvt, delgroup, deluser, devfsd, df, diff, dirname, dmesg, dnsd, dos2unix, dpkg, dpkg_deb, du, dumpkmap, dumpleases, e2fsck, echo, ed, eject, env, ether_wake, expr, fakeidentd, false, fbset, fdflush, fdformat, fdisk, find, fold, free, freeramdisk, fsck, fsck_minix, ftpget, ftpput, fuser, getopt, getty, grep, gunzip, gzip, halt, hdparm, head, hexdump, hostid, hostname, httpd, hwclock, id, ifconfig, ifdown, ifup, inetd, init, insmod, install, ip, ipaddr, ipcalc, ipcrm, ipcs, iplink, iproute, iptunnel, kill, killall, klogd, lash, last, length, less, ln, loadfont, loadkmap, logger, login, logname, logread, losetup, ls, lsattr, lsmod, lzmacat, makedevs, md5sum, mdev, mesg, mkdir, mke2fs, mkfifo, mkfs_minix, mknod, mkswap, mktemp, modprobe, more, mount, mountpoint, mt, mv, nameif, nc, netstat, nice, nohup, nslookup, od, openvt, passwd, patch, pidof, ping, ping6, pivot_root, poweroff, printenv, printf, ps, pwd, rdate, readlink, readprofile, realpath, reboot, renice, reset, rm, rmdir, rmmod, route, rpm, rpm2cpio, run_parts, runlevel, rx, sed, seq, setarch, setconsole, setkeycodes, setlogcons, setsid, sha1sum, sleep, sort, start_stop_daemon, stat, strings, stty, su, sulogin, sum, swapoff, swapon, switch_root, sync, sysctl, syslogd, tail, tar, tee, telnet, telnetd, test, tftp, time, top, touch, tr, traceroute, true, tty, tune2fs, udhcpc, udhcpd, umount, uname, uncompress, uniq, unix2dos, unlzma, unzip, uptime, usleep, uudecode, uuencode, vconfig, vi, vlock, watch, watchdog, wc, wget, which, who, whoami, xargs, yes, zcat, zcip
Which is more commands than one person really needs.