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Which option is it? when I put the number in it just says

pc@pc:~$ 0

0: command not found

pc@pc:~$ cd ~/catkin_ws/src/ pc@pc:~/catkin_ws/src$ cd .. pc@pc:~/catkin_ws$ rosdep install pioneer3at

ERROR: Rosdep cannot find all required resources to answer your query Missing resource pioneer3at ROS path [0]=/opt/ros/hydro/share/ros ROS path [1]=/opt/ros/hydro/share ROS path [2]=/opt/ros/hydro/stacks

Originally posted by HelpwithUbuntu on ROS Answers with karma: 15 on 2014-08-16

Post score: 0

Original comments

Comment by gvdhoorn on 2014-08-16:
So what do you think cd does?


1 Answer 1


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cd .. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< (it simply changes the directory to the one that contains the current one. In Windows parlor: we go up, to the folder that is the parent of the current folder.) I have no idea what any of this is. I understand what CD does but not CD .. what does the two dots mean? none of the links had any info on them.

"the links" actually explained that to you (copied from A very, very gentle introduction to the Linux Command Line):

Let’s back up and try again:

chris@bobo:~/Desktop$ cd ..

The two dots tell us to move up a level in our directory structure.

But, just to be sure, here is another example, can't make it any simpler than this:

# we are currently here
pc@pc:~$ pwd

# now we go one directory 'up'
pc@pc:~$ cd ..

# and now we are here
pc@pc:~$ pwd

In every directory there are at least two "other" directories: "." (dot): the current directory, and ".." (double dot): the parent directory. cd .. tells bash (or whatever your shell is) to change the directory to the parent directory (whatever that currently is).

Again: I think you should first get acquainted with Linux and the command line a bit more. Otherwise you'll continue to run into issues like this.

Originally posted by gvdhoorn with karma: 86574 on 2014-08-16

This answer was ACCEPTED on the original site

Post score: 4

Original comments

Comment by HelpwithUbuntu on 2014-08-16:
I could not see the the two dots on this laptop, I never relieved that CD .. was a command, because when people are typing and want to end a sentence they use .

Comment by tfoote on 2014-08-17:
@HelpwithUbuntu please accept the answer using the checkmark at the left so people know it's resolved.


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