检查 roscore 是否正常打开
[ERROR] Failed to contact master at [localhost:11311]. Retrying...
[ERROR] [1446531999.044935824]: [registerPublisher] Failed to contact master at [localhost:11311]. Retrying...
解决:请检查 roscore 是否正常打开。
每次进行运行测试时都要首先运行 roscore。
关于rosdep update
reading in sources list data from /etc/ros/rosdep/sources.list.d
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml]:
<urlopen error _ssl.c:495: The handshake operation timed out> (https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml)
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml
ERROR: error loading sources list:
The read operation timed out
不知道如何解决,求吧友解惑
http://tieba.baidu.com/p/4877135262
我也出现此问题,然后我执行了以下就可以了:
sudo apt-get update
sudo apt-get install python-rosdep
程序“rosdep”尚未安装
您可以使用以下命令安装:
sudo apt install python-rosdep
加锁
错误提示:
E: 无法获得锁 /var/lib/apt/lists/lock – open (11: 资源暂时不可用)
E: 无法对目录 /var/lib/apt/lists/ 加锁
解决办法一:
面对这个问题,有人直接在终端中输入命令:
sudo rm /var/cache/apt/archives/lock
sudo rm /var/lib/dpkg/lock
Ubuntu获取root权限
1.临时获取root权限:
Ctrl+Alt+T 快捷键打开终端
#sudo -i //获取root权限后更改当前路径为根目录/root
#sudo -s //获取root权限后仍在当前目录下
[sudo] password for ***: //输入开机密码
root@***:~# //临时获取root
2.永久root权限:(以root账户登录)
先按1.中方法临时获得root权限
#cd /etc/lightdm
#gedit lightdm.conf
打开编辑器,在最后加上两行:
greeter-show-manual-login=true
allow-guest=false
#passwd root
输入新的Unix密码:
重新输入新的 UNIX密码:
passwd:已成功更新密码