Shader code and camera Monobehaviour to render the example on The Book of Shaders pg. 5 in Unity 5.4.1 -- https://thebookofshaders.com/05/ -- https://gist.github.com/chuckbergeron/50adf7f5099bc85a25c9606246aca963

plot.shader

Shader "Custom/PlotShader"
{

	Properties
	{
		_MainTex ("Texture", 2D) = "white" {}
	}

	SubShader
	{
		// No culling or depth
		Cull Off ZWrite Off ZTest Always

		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag

			#include "UnityCG.cginc"

			struct appdata
			{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
			};

			struct v2f
			{
				float2 uv : TEXCOORD0;
				float4 vertex : SV_POSITION;
			};

			v2f vert (appdata v)
			{
				v2f o;
				o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
				o.uv = v.uv;
				return o;
			}

			sampler2D _MainTex;

			// Plot a line on Y using a value between 0.0-1.0
			float plot(fixed2 st, float pct)
			{
			  return  smoothstep( pct-0.02, pct, st.y) -
			          smoothstep( pct, pct+0.02, st.y);
			}

			fixed4 frag (v2f i) : SV_Target
			{
				float2 st = i.vertex.xy/_ScreenParams.xy;

		    		float y = st.x;

		    		float3 color = float3(y, y, y);

		    		// Plot a line
		    		float pct = plot(st, y);
		    		color = (1.0 - pct) * color + pct * float3(0.0, 1.0, 0.0);

				return float4(color, 1.0);
			}
			ENDCG
		}
	}

}