Re: problem with wget -O
On Thursday 28 January 2021 11:10:48 Greg Wooledge wrote:
> On Thu, Jan 28, 2021 at 10:06:25AM -0600, David Wright wrote:
> > Perhaps file a bug against that page. It appears that they were
> > using -O merely to avoid overwriting http://master.zip with the
> > second instance of wget. The manpage expressly advises against doing
> > that: "Use of -O is not intended to mean simply "use the name file
> > instead of the one in the URL". They should just use mv after each
> > wget to place the zip files where they want them.
>
> If -O is bad, then what are you supposed to use instead?
>
> If you need to "use mv after each wget", how do you know the name of
> the file that wget used? And why can't you simply tell wget to use
> the filename you *want* it to be written to? Why would you need to do
> this weird two-step process?
for a change, I am 100% with Greg W., in fact, if the file already
exists, wget should assume a bad copy was previously obtained, and
should then very cheerfully over write the existing file.
The full instructions apparently will only work with an old ubuntu
install, so needs updated for debian:
copy/paste from opencv install web page
---------------------------------
Build core modules
# Install minimal prerequisites (Ubuntu 18.04 as reference)
sudo apt update && sudo apt install -y cmake g++ wget unzip
# Download and unpack sources
wget -O opencv.zip https://github.com/opencv/opencv/archive/master.zip
unzip opencv.zip
# Create build directory
mkdir -p build && cd build
# Configure
cmake ../opencv-master
# Build
cmake --build .
Build with opencv_contrib
# Install minimal prerequisites (Ubuntu 18.04 as reference)
sudo apt update && sudo apt install -y cmake g++ wget unzip
# Download and unpack sources
wget -O opencv.zip https://github.com/opencv/opencv/archive/master.zip
wget -O opencv_contrib.zip
https://github.com/opencv/opencv_contrib/archive/master.zip
unzip opencv.zip
unzip opencv_contrib.zip
# Create build directory and switch into it
mkdir -p build && cd build
# Configure
cmake -DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib-master/modules ../opencv-master
# Build
cmake --build .
-------------------------
But while I've been thru that from square 0 several times, scrolling back
thru the history discloses many failures due to not finding stuff on
debian while doing the first cmake. Needless to say, I've not done any
install.
Blowing all that way, and using git, gets me 476 megs of src, so
mkdir build && cd build,
then the configure line is next:
cmake ../opencv
But: I think I forgot to blow away the older build dir
I did, redone it, and now it almost works, but with lots of fails from
missing deps I cannot fix with synaptic.
And I apparently cannot run grep to properly detect the failed string
from the configure steps output, the
cmake ../opencv | grep -i failed -
command does not have any valid, contains "Failed" output. But the
scrollback has a dozen or more instances including a total failure for
anything related to gtk2+ or gtk3+
No use trying a build.
So I installed, with synaptic, as much of opencv as it would let me,
which excludes the -dev packages.
Now what, there is no trace of it in the menu's, anyplace.
I saw, on you-tube, opencv doing some great stuff in collaboration with
linuxcnc, like automatic edge finding by actually commanding the machine
to move, doing it very quickly at the machines top speed. We allready
have utilities that allow us to place a workpiece to be carved on the
machines table without regard to how square it is with the table as we
can rotate the co-ordinate map to match the workpieces orientation. But
finding those two locations to use as a reference either needs a very
expensive touch probe, or a camera and lots of fidgity teeny moves to
find those reference points. The camera can with this ability to move
the machine, reduce an half hours setup time using the $1000 probe to
find these reference points used for the correction calculations, to 2
or so minutes using the camera instead of the touch probe.
So, now that I have as much of it installed as synaptic allows, back to
the lcnc list to see if the needed additions to the lcnc *.ini file can
be shared.
Until then, lets put this thread to rest. wget was fixed by blowing away
my /home/me/.wgetrc
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>
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