如何对gstreamer命令行的接收器定义的引号内的引号进行转义

Question

How to I use quotes in quotes for gstreamer command line. This is gstreamer version 1.14.4 and ubuntu version 4.9.140-tegra using bash shell all running on Jetson Nano dev system.

I tried various escape methods and none worked.

The following has double quotes with quotes inside the sink definition and doesn't work.

gst-launch-1.0 playbin uri=file:///home/tom/Videos/UHD_demo_Nature.mp4 sink="glupload !  glshader fragment="\"`ca
t testfrag.frag`\"" ! glimagesinkelement"

I assume it's an escape sequence issue, I tried bunch of ways to escape but I would rather not bias anyone looking at this problem. The opengl fragment is correct and works using a simple command line example:

gst-launch-1.0 videotestsrc ! glupload ! glshader fragment="\"`cat testfrag.frag`\"" ! glimagesink

Any ideas is this a command shell issue or gstreamer issue I need to correct concerning double quotes.

Here is the fragment:

\#version 100

  #ifdef GL_ES

  precision mediump float;

  #endif

  varying vec2 v_texcoord;

  uniform sampler2D tex;

  uniform float time;

  uniform float width;

  uniform float height;
  vec4 myColor;


  void main () {

        myColor = texture2D( tex, v_texcoord );
        gl_FragColor = myColor;
        gl_FragColor.r = myColor.b;
        gl_FragColor.b = myColor.r;

  }

When I run the command line I get the following error:

Generates an error message:
WARNING: erroneous pipeline: no element "100"

Answer 1

Have you tried %22 to escape a quotationmark?

This site shows the html encodings, I got that idea from this line:

The query string for the new URI with '&' separating query elements. Elements containing '&' characters should encode them as "%26".

from this website.