GLSL: Accessing one row of the texture

//Fragment Shader Program to access texture and just copying one row to other

uniform sampler2D textureX;
uniform float        texRows;
uniform float        texCols;

void main(void) {
//cols                rows
vec4 x            = texture2D(textureX, vec2(gl_TexCoord[0].s, gl_TexCoord[0].t+1.0/texRows));
gl_FragColor    = x;

}