Some operations related to embedded Linux (e.g. Kernel build etc) requires the use of toolchain, thus the first command is:
$ source /opt/fslc-x11/2.2.1/environment-setup-armv7at2hf-neon-fslc-linux-gnueabi
I'd like to place this command inside a .sh script for Ubuntu: what's the right way?
Related
I am installing a Java GUI application with few jars and related resource in linux in some directory.
The install script is written using bash script. If I try to execute the same script then the same application is installed in some other location.
What is the correct way to avoid multiple installation. I want to identify the already existing program regardless of the user.
I would use something like this:
compgen -c | grep "your program name"
Compgen gives out all commands and paths
I'm trying to run a Makefile for building a kernel module in QtCreator. I can successfully invoke the make file from the command line.
My assumption was that this shouldn't be a problem to set also in QtCreator by defining the build step as a custom command make.
It seems however that QtCreator is introducing some other working paths instead.
As the showcase above points, both the working directory and the script absolute path are set to /home/user/module which is the path in which the correct Makefile resides.
However, QtCreator seems to be searching for the Makefile at /home/user/Qt/Tools/QtCreator/bin/Makefile: No such file or directory.
Am I missing a setting somewhere or is this a bug?
You are using the PWD environment variable in your makefiles. This environment variable is updated only by a shell though, and custom process steps are not executed in a shell by default, but started directly as a child process. This means that PWD will stay as it is shown in the "Run Environment" section of the run configuration instead of being changed to the working directory of the step.
If your custom step depends on features of the shell, you should run it in a shell, i.e. set the "Command" to /bin/sh (or /bin/bash or whatever you prefer), and the "Arguments" to -c make (or whatever you need to pass to your preferred shell to execute a command).
What does 'export' do when used in a command line.
For example, and this is only one example, I build a number of C++ libraries and for a library such as zlib-1.2.8 I need to specify the install directories.
To do this I need to do the following in MSYS command line interface. This is just one example
export LIBRARY_PATH="c/libraries/libs;$LIBRARY_PATH"
Would anyone know what the command 'export' actually does in this instance?
Does it permanently install a record for MSYS to user later on when looking for dependencies such as ZLIB . My using make install the zlib library file is placed in this directory.
OR, when I close MSYS is this LIBRARY_PATH lost from MSYS memory?
Thanks
This is the bash syntax to set an environment variable. Using export allows the variable to be seen outside the script in which it's defined.
Environment variables only affect the msys process and any child processes started from that shell. If you want it to persist after you close the command line and start a new one, you will need to put it into a script such as .bashrc
I have a book called Beginning Lua Programming which is suppose to go over the raw basics but it is sort of leaving me stranded. Here is an effort to condense 3 pages:
QUOTE:
The following environment variables are recommended for Windows:
UTIL_DIR=c:\program files\utility
LUA_DIR=c:\program files\lua\5.1
LUA_CPATH=?.dll;%LUA_DIR%\?.dll
LUA_PATH=?.lua;%LUA_DIR%\?.lua
The UTIL_DIR variable identifies the utility directory you created in the preceding section.
After this, there is a segment about setting the 'windows search path' for lua. Basically, it tells me to look up the output of 'doskey /?' and 'path' and figure it out myself. I have no idea what these do, how to use them, and what the difference between them is.
I'm at my wits end. A detailed explanation or a link to a detailed blog/article or youtube video is EXTREMELY appreciated!
There are a few ways to get Lua working on your machine. If you just want to a functional Lua environment in a hurry with minimal fuss then consider downloading one of the precompiled Lua binaries. The common ones being Lua for Windows and LuaBinaries.
Building Lua with Mingw isn't too difficult:
First get your desired Lua version here.
Extract the tar file containing Lua's source somewhere. For this example, I'll assume you extracted to c:\lua
If you have Msys already set up, you can run the make file from that environment. From the Msys shell, you can build lua with the follow commands:
cd /c/lua
make PLAT=mingw
make install
You should find lua.exe and luac.exe somewhere in there after the build completes. Lua should be ready for use at this point.
The regular cmd.exe shell can work too with some changes to the commands:
cd lua
mingw32-make PLAT=mingw
The make install assumes a *nix environment and so doesn't work under a normal windows cmd shell. In this case you can just manually copy the compiled files from .\lua\src to where you want or you can just run it directly from there if desired.
I have made a few python scripts, but is there an easier way to run them? I am using cygwin.
python "C:\Users\Desk\Dropbox\scripts\wsort.py" > data11414_unsorted.txt < data11414_sorted.txt
I want something like this (not typing the path name or "python"):
wsort > data11414_unsorted.txt < data11414_sorted.txt
where wsort is a link to my real wsort.py
Add a
Shebang
to the script
#!/bin/python
then invoke like this
wsort.py > data11414_unsorted.txt < data11414_sorted.txt
First, your question has a Windows-style path (backslashes, beginning with C:) rather than a Cygwin path (/cygdrive/c/Users/Desk/Dropbox/scripts/wsort.py). That implies you're not actually using Cygwin, or if you are, you're ignoring a bunch of warnings.
The below assumes you're using Cygwin Bash (which should be what you get if you start Cygwin Terminal from the Start Menu) and Cygwin Python (which you've installed using Cygwin's setup.exe, not a Windows Python installer). If your not, you're making life more difficult for yourself than you need to.
That out the way, there's a bunch of steps you need to take:
First, make the script executable. Use the chmod command for that, from a Cygwin Bash shell:
chmod +x /cygdrive/c/Users/Desk/Dropbox/scripts/wsort.py
Second, tell the system how to execute it. Add the following line to the top of the script:
#!/bin/python
(That's a "shebang". Python sees it as a comment, so doesn't do anything with it, but Cygwin and other Linux-like systems will use that line to see which program to run the script with. In this case, Python.)
Third, make sure your line endings are correct. Cygwin expects Linux line endings and will fail without them. This may not be a problem, but there's no harm in doing this. Run the following command:
dos2unix /cygdrive/c/Users/Desk/Dropbox/scripts/wsort.py
At this point, you'll be able to call the script by specifying the full path to it in Cygwin. You can't yet run it without specifying where the script is explicitly.
The fourth step is making sure the script is "in your path", ie in one of the folders where Cygwin looks for scripts to run. There are lots of ways to do this, but the most sensible is probably to just add your scripts directory to your path. The following command will add your scripts directory to your path whenever you start a new Cygwin session:
echo 'PATH="/cygdrive/c/Users/Desk/Dropbox/scripts:$PATH"' >>~/.bashrc
You will need to restart your Cygwin terminal for that to take effect, however.
At that point, you'll be able to run the script in Cygwin just by typing wsort.py (and thus use it with redirections and so forth as in your question).
Finally, to be able to call it simply as wsort, there's a number of options. The obvious one is just renaming the file. More usefully (and without copying the file or doing anything liable to break with Dropbox syncing things), try creating an alias:
echo 'alias wsort=wsort.py' >>~/.bashrc
Again, you'll need to restart your Cygwin terminal for that to take effect.
Maybe use an alias ?
alias wsort = "Command_Used"