Debian 安装完成找不到命令解决方法

#查看当前$PATH
root@debian:/home/user# echo $PATH
/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games

root@debian:/home/user# export PATH=$PATH:/sbin/
root@debian:/home/user#

#切换到root目录
root@debian:/home/user# cd ~
root@debian:~# 
#编辑文件
root@debian:~# vim .bashrc

export PATH=$PATH:/usr/sbin

# ~/.bashrc: executed by bash(1) for non-login shells. 
 
# Note: PS1 and umask are already set in /etc/profile. You should not 
# need this unless you want different defaults for root. 
# PS1='${debian_chroot:+($debian_chroot)}\h:\w\$ ' 
# umask 022 
 
# You may uncomment the following lines if you want `ls' to be colorized: 
# export LS_OPTIONS='--color=auto' 
# eval "`dircolors`" 
# alias ls='ls $LS_OPTIONS' 
# alias ll='ls $LS_OPTIONS -l' 
# alias l='ls $LS_OPTIONS -lA' 
# 
# Some more alias to avoid making mistakes: 
# alias rm='rm -i' 
# alias cp='cp -i' 
# alias mv='mv -i' 
export PATH=$PATH:/usr/sbin

root@debian:~# source ~/.bashrc
root@debian:~#

root@debian:~# echo $PATH
/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/usr/sbin