Replace/override system commands

[hollson]

Replace/override system commands to force users to use sdk libraries

#!/bin/bash

# 开启命令别名
shopt -s expand_aliases

# 给系统echo函数使用别名
alias sys_echo="command echo"

# 自定义函数(偷梁换柱)
echo() {
    sys_echo "Custom echo"
}

# 测试
sys_echo "System echo"
echo