路径
/为所有Linux发行版的根目录。
/bin即binary，存放着最常使用的命令。如文件/目录操作，文件压缩，网络管理，进程管理，模块管理累工具。/sbin即super user's binary，存放系统管理员才有权限使用的系统管理程序。
/usr路径下存放着很多重要的程序和文件，该目录类似于Windows系统中的Program Files目录。
-
/usr/bin存放系统用户使用的应用程序。 -
/usr/sbin存放超级用户才能使用的管理程序和系统守护程序。 -
sum
/bin和/usr/bin是给系统用户用的(除root用户外)
/sbin和/usr/sbin是给root用户用的。
命令数量
wc -l 用于计算文本内容的行数(Word Count --line-numbers)
wyj@g40:~$ ll /bin | wc -l
166
wyj@g40:~$ ll /sbin | wc -l
174
wyj@g40:~$ ll /usr/bin | wc -l
1666
wyj@g40:~$ ll /usr/sbin | wc -l
195
可以看出，/usr/sbin目录中的程序数量是最多的。
Others
binbinary 二进制，可执行程序，命令。sbinsuper user(超级用户)的可执行命令。usr
usr是user的缩写，是曾经的HOME目录(如minix)。用于存放二进制命令，文档，库，头文件，各类程序等。
现在是Unix System Resource的缩写，即Unix系统资源，用于存放程序和数据，其他的都在HOME目录下。
Additional
ls /bin
bash cp fusermount loginctl ntfs-3g plymouth sync unicode_start
brltty cpio getfacl lowntfs-3g ntfs-3g.probe ps systemctl vdir
bunzip2 dash grep ls ntfscat pwd systemd wdctl
busybox date gunzip lsblk ntfscluster rbash systemd-ask-password which
bzcat dd gzexe lsmod ntfscmp readlink systemd-escape whiptail
bzcmp df gzip mkdir ntfsfallocate red systemd-hwdb ypdomainname
bzdiff dir hciconfig mknod ntfsfix rm systemd-inhibit zcat
bzegrep dmesg hostname mktemp ntfsinfo rmdir systemd-machine-id-setup zcmp
bzexe dnsdomainname ip more ntfsls rnano systemd-notify zdiff
bzfgrep domainname journalctl mount ntfsmove run-parts systemd-sysusers zegrep
bzgrep dumpkeys kbd_mode mountpoint ntfsrecover sed systemd-tmpfiles zfgrep
bzip2 echo kill mt ntfssecaudit setfacl systemd-tty-ask-password-agent zforce
bzip2recover ed kmod mt-gnu ntfstruncate setfont tar zgrep
bzless efibootdump less mv ntfsusermap setupcon tempfile zless
bzmore efibootmgr lessecho nano ntfswipe sh touch zmore
cat egrep lessfile nc open sh.distrib true znew
chacl false lesskey nc.openbsd openvt sleep udevadm
chgrp fgconsole lesspipe netcat pidof ss ulockmgr_server
chmod fgrep ln netstat ping static-sh umount
chown findmnt loadkeys networkctl ping4 stty uname
chvt fuser login nisdomainname ping6 su uncompress
ls /sbin
acpi_available dmstats getcap iwevent mkfs.msdos pccardctl swaplabel
agetty dosfsck getpcaps iwgetid mkfs.ntfs pivot_root swapoff
alsa dosfslabel getty iwlist mkfs.vfat plipconfig swapon
apm_available dumpe2fs halt iwpriv mkhomedir_helper plymouthd switch_root
apparmor_parser e2fsck hdparm iwspy mkntfs poweroff sysctl
badblocks e2image hwclock kbdrate mkswap rarp tc
blkdeactivate e2label ifconfig killall5 modinfo raw telinit
blkdiscard e2undo ifdown ldconfig modprobe reboot tipc
blkid fatlabel ifquery ldconfig.real mount.fuse regdbdump tune2fs
blockdev fdisk ifup lilo mount.lowntfs-3g resize2fs u-d-c-print-pci-ids
bridge findfs init logsave mount.ntfs rmmod udevadm
brltty fixparts insmod losetup mount.ntfs-3g route umount.udisks2
brltty-setup fsck installkernel lsmod nameif rtacct unix_chkpwd
capsh fsck.cramfs ip lspcmcia ntfsclone rtmon unix_update
cfdisk fsck.ext2 ip6tables mii-tool ntfscp runlevel ureadahead
cgdisk fsck.ext3 ip6tables-restore mkdosfs ntfslabel runuser wipefs
chcpu fsck.ext4 ip6tables-save mke2fs ntfsresize setcap wpa_action
crda fsck.fat ipmaddr mkfs ntfsundelete setvtrgb wpa_cli
ctrlaltdel fsck.minix iptables mkfs.bfs on_ac_power sfdisk wpa_supplicant
debugfs fsck.msdos iptables-restore mkfs.cramfs pam_extrausers_chkpwd sgdisk xtables-multi
depmod fsck.vfat iptables-save mkfs.ext2 pam_extrausers_update shadowconfig zramctl
devlink fsfreeze iptunnel mkfs.ext3 pam_tally shutdown
dhclient fstab-decode isosize mkfs.ext4 pam_tally2 slattach
dhclient-script fstrim iw mkfs.fat parted start-stop-daemon
dmsetup gdisk iwconfig mkfs.minix partprobe sulogin
ls /usr/sbin
aa-remove-unknown cupsctl iio-sensor-proxy pppconfig update-dictcommon-hunspell
aa-status cupsd invoke-rc.d pppd update-fonts-alias
accept cupsdisable ip6tables-apply pppdump update-fonts-dir
accessdb cupsenable ippserver pppoeconf update-fonts-scale
acpid cupsfilter ippusbxd pppoe-discovery update-grub
addgnupghome cups-genppdupdate iptables-apply pppstats update-grub2
addgroup cupsreject irqbalance pptp update-grub-gfxpayload
add-shell delgroup irqbalance-ui pptpsetup update-gsfontmap
adduser deluser ispell-autobuildhash pwck update-icon-caches
alsabat-test dkms iucode_tool pwconv update-inetd
alsactl dmidecode iucode-tool pwunconv update-info-dir
alsa-info dnsmasq kerneloops readprofile update-initramfs
anacron dpkg-preconfigure keytab-lilo reject update-java-alternatives
apparmor_status dpkg-reconfigure ldattach remove-default-ispell update-lilo
applygnupgdefaults e2freefrag liloconfig remove-default-wordlist update-locale
aptd e4crypt lilo-uuid-diskid remove-shell update-mime
arp e4defrag locale-gen rfkill update-passwd
arpd fdformat logrotate rmt update-pciids
aspell-autobuildhash filefrag lpadmin rmt-tar update-pepperflashplugin-nonfree
avahi-autoipd gdm3 lpc rsyslogd update-rc.d
avahi-daemon genl lpinfo rtcwake update-usbids
biosdecode getweb lpmove rtkitctl upgrade-from-grub-legacy
bluetoothd gnome-menus-blacklist make-ssl-cert saned usb_modeswitch
chat groupadd mkinitramfs select-default-ispell usb_modeswitch_dispatcher
chgpasswd groupdel mklost+found select-default-wordlist usbmuxd
chmem groupmems mkrescue service useradd
chpasswd groupmod ModemManager setvesablank userdel
chroot grpck netplan spice-vdagentd usermod
cpgr grpconv NetworkManager tarcat uuidd
cppw grpunconv newusers tcpdump validlocale
cracklib-check grub-bios-setup nfnl_osf thermald vcstime
cracklib-format grub-install nologin tzconfig vigr
cracklib-packer grub-macbless ownership ufw vipw
cracklib-unpacker grub-mkconfig pam-auth-update update-ca-certificates visudo
create-cracklib-dict grub-mkdevicemap pam_getenv update-cracklib vpddecode
cron grub-probe pam_timestamp_check update-default-aspell zic
cupsaccept grub-reboot paperconfig update-default-ispell
cupsaddsmb grub-set-default popcon-largest-unused update-default-wordlist
cups-browsed iconvconfig popularity-contest update-dictcommon-aspell
