# which 命令 >[info] 查找命令所在的路径，搜索范围来自全局环境PATH变量对应的路径 which命令行查找的命令所在路径,在$PATH环境中可以通过打印`echo $PSTH`查看系统环境变量路径(以:分割) ~~~ which useradd # /usr/sbin/useradd find / -type f -name 'useradd' # /usr/sbin/useradd # /etc/default/useradd whereis -b useradd # useradd: /usr/sbin/useradd locate useradd # /etc/default/useradd # /usr/sbin/luseradd # /usr/sbin/useradd # ... ~~~