I installed OCaml for Windows, using this graphical Installer..
The installation is complete, next step is installing the package "depext-cygwinports".
However according to this, i need to add an entry to the $PATH variable before installing the actual package.. And the entry that i have to add has to be inserted in front of "/usr/bin", not after it.
How can i do this?
And how can i apply this change in $PATH permanently, without having to add the entry for every Bash session?
Related
I want to permanently add /mingw64/bin to the MSYS2 PATH.
I have tried:
export PATH=$PATH:/mingw64/bin
It works until I exit.
After I restart MSYS2 the path has reset to what it was before.
What do I need to do to add /mingw64/bin to the PATH so the change persists after I quit and restart the MSYS2 console?
You shouldn't manually add /??/bin to the PATH in the MSYS2 terminal.
It happens automatically (along with other changes to environment variables) when you open the terminal for the environment you want to use.
There should be different shortcuts for different environments, the one you're looking for should be named along the lines of ... MinGW 64-bit.
The shortcuts point to executables in C:\msys64, which you can run directly (this one is mingw64.exe).
I have a kinda weird problem. I'm currently messing around with the VRX-Simulator, which simulates an unmanned-watersurface-vehicle.
For the installation I followed the guide on https://bitbucket.org/osrf/vrx/wiki/tutorials/SystemSetupInstall.
Then I tried to modify some of the files and tried to rebuild the project.
This was the point when I noticed it always used the "old" version of my simulation within gazebo.
From now on no matter what I did (I even deleted the whole catkin workspace folder) ROS somehow managed to always launch the original version of my simulation even without any build/src folder existing when I used roslaunch.
roslaunch vrx_gazebo sandisland.launch
So my question would be how can I get rid of my simulation/model and where does ros/gazebo cache my simulation?
You most probably installed the package with the command from the tutorial sudo apt install ros-melodic-vrx-gazebo. So the package launched with roslaunch vrx_gazebo sandisland.launch was not in your catkin workspace. If you want to get rid of it you can uninstall it with sudo apt remove ros-melodic-vrx-gazebo. But this is not strictly necessary.
There are several ways to find out where some ros package is located, try running some of these commands:
rospack find vrx_gazebo will show you where the package used is located
roscd vrx_gazebo will take you to the folder where it is installed something like
/opt/ros/melodic/share/vrx_gazebo
If you also followed the tutorials installing from source code then the issue most likely was not sourcing the built packages. The last line of the guide is a bit misleading. The line *Remember to run this command every time you open a new terminal. is meant to reference the command source ~/vrx_ws/devel/setup.bash
Whether the installed package or the package built from source is used depends on which order they are listed in the environment variable ROS_PACKAGE_PATH. This variable is modified by both source /opt/ros/melodic/setup.bash and source ~/vrx_ws/devel/setup.bash. So have a look at the variable after each step with printenv | grep ROS or echo $ROS_PACKAGE_PATH. Theoretically if you source your terminal in the order I had the source commands it should be using the package built from source, you can verify with the rospack find ... and roscd ... commands mentioned earlier.
In the end it is probably easier to add the sourcing commands to your .bashrc file so you would not forget to source the terminals as mentioned in the ROS installation tutorial. You can add the sourcing of the workspace to the the same file, you will just have to be aware that you would need to change the file, should you want to use a different workspace.
http://wiki.ros.org/melodic/Installation/Ubuntu#melodic.2BAC8-Installation.2BAC8-DebEnvironment.Environment_setup
relevant command from the tutorial:
echo "source /opt/ros/melodic/setup.bash" >> ~/.bashrc
you could do the same for the workspace:
echo "source ~/vrx_ws/devel/setup.bash" >> ~/.bashrc
And after running those commands run exec bash to get the changes into the current terminal. All future terminals will have those commands already loaded.
I was having some trouble installing the gem libv8. Apparently I need to have python installed. I installed Python and was attempting to update my path with command from another forum:
SET PATH=C:[Ruby Directory]\bin;C:[Python Directory]
or in my case:
SET PATH=C:\Ruby192\bin;C:\Python27
I am not strong with paths and I can't figure out what I did. Now my environment can't find my Ruby directory.
Can someone explain what I did and how I might fix it?
That is most likely because your PATH variable already had a bunch of stuff that you simply throwed away with that line:
echo %PATH%
# a bunch of stuff
SET PATH=C:\Ruby192\bin;C:\Python27
echo %PATH%
# C:\Ruby192\bin;C:\Python27
You can try to append to it instead instead:
set PATH=%PATH%;C:\Ruby192\bin;C:\Python27
echo %PATH%
# a bunch of stuff plus C:\Ruby192\bin;C:\Python27
This change will be avalid for your terminal session only. Closing it and open again should restore the default path. If you need to make it permanent, you need to change your path throught the windows (for example, following this instructions)
I am following the tutorial : http://java.sun.com/developer/onlineTraining/Programming/JDCBook/jniexamp.html
when I reach the part where I am supposed to set the library path :
Unix or Linux:
LD_LIBRARY_PATH=`pwd`
export LD_LIBRARY_PATH
Windows NT/2000/95:
set PATH=%path%;
Neither of these work in cygwin. I keep getting an error when trying to run my program.
Cygwin doesn't use LD_LIBRARY_PATH, it looks for shared libraries in PATH, so try:
export PATH=`pwd`:$PATH
That will add the current directory to the front of the PATH.
Is that
LD_LIBRARY_PATH=$(pwd)
and you just messed up the html, or are you really running:
LD_LIBRARY_PATH=pwd
If the latter, try adding the $() to get the current working directory into the path. Also, you can
echo $LD_LIBRARY_PATH
to ensure it contains what you want. You might consider doing
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$(pwd)
to avoid discarding previous contents of the path.
So I installed Ruby On Rails using the Windows Installer.
Now the startup guides says I have to start up an Terminal and run the Rails command to make a project. I don't have a terminal, so how do I execute a Rails command and make a project??
The CMD command line in Windows does not recognize "rails"
I don't think it is an PATH problem, because when I'm in the "Bin" directory, there is "rails.bat" and "rails" with no extension. If I run Rails.bat I get "The filename, directory name, or volume label syntax is incorrect."
I get that message with whatever Argument I pass to it.
It seems to be a bug in the rails.bat file because of double-quotes, like:
#"ruby.exe"" "%~dpn0" %*
Remove the double quotes:
http://sepitfalls.blogspot.com/2008/12/updateing-rubygems-broke-gem-command.html
To get a terminal
Start > Run... or Windows key + R
Type "cmd" and hit enter.
To add a folder to the command line's path
On Windows XP (Vista is similar)
Start > Control Panel > System
Click the "Advanced" tab
Click "Environmental Variables"
Under "System Variables" double click on Path and edit accordingly.
You will need to open a new command line in order to get the updated path to take affect. With XP, I've had to reboot to force it to take affect but it shouldn't be necessary.
The Path variable is a semi-colon seperated list of folders in which the Command Line or "terminal" looks for commands.
You'll probably have to find the rails command yourself. I would try looking for a rails.bat or rails.cmd file.
I think they mean the command window. Try running it from a command line.
I dont know where the Windows Ruby on Rails intaller places its files, but the ultimately solution is that you need to make sure that the "rails" command is is your PATH - which you can view/modify by right-clicking My Computer, selecting Properties, going to the Advanced tab and then clicking on "Environment Variables" and then scrolling down until you see "PATH" and adjusting it accordingly. You probably need to find the directory where the "rails" command lives and append to the end of the existing PATH entry, inserting a ";" before you enter the new path to append it to the existing PATH.
So find where "rails" is and add its directory to your PATH.
You probably have to change your PATH in Windows to point to wherever the rails executable has been installed.
The PATH environment variable is used to determine where Windows looks for stuff; when you type, for instance, 'calc' Windows will hunt through its PATH and eventually find and run C:\Windows\calc.exe. In your case, the PATH doesn't include the directory you need, so Windows isn't searching in that directory for rails.exe when you type "rails."
To fix this, right click on "My Computer" -> "Properties" -> "Advanced" -> "Environment Variables" and then modify the PATH one to include the directory your rails.exe is in.
I recommend using cygwin for Rails development on windows - far too much of the community is using *nix. If you install the development tools package you'll automatically have svn, git and other doo-dads that you'll eventually need relating to various rails plugin installation. If you want to deploy using capistrano the installation is identical to all the instructions you find. Plus other tips and tricks people will reference will work exactly the same for you as it does for them, whereas some things are different for native windows and all the accessory tools have to be installed separately.