The following command seems to work, when typed on bash:
$ gmic http://www.particularart.com/static/media/uploads/command_reference/repeat/ampersand_goudybl1911.svg -negative[-1] -blur[-1] 3,1,0 100% 100% -append c -expand_x {{w}/2} 100%,100%,100%,100% -append[-2,-1] y 100%,100%,100%,100% -repeat {360/6} 'k={6*($>+1)}' --rotate[0] '{$k}',2,1,255,255 -apply_channels[-1] \"-add \"\$k,hsl_h -blend[-2,-1] negation,0.7 -done -rm[-2]
though I admit that for such long command lines, I would rather suggest using a custom command file instead, like putting all this in file foo.gmic:
# File `foo.gmic`
foo :
-input http://www.particularart.com/static/media/uploads/command_reference/repeat/ampersand_goudybl1911.svg
-negative[-1]
-blur[-1] 3,1,0
100% 100%
-append c
-expand_x {{w}/2}
100%,100%,100%,100%
-append[-2,-1] y
100%,100%,100%,100%
-repeat {360/6}
k={6*($>+1)}
--rotate[0] {$k},2,1,255,255
-apply_channels[-1] "-add "$k,hsl_h
-blend[-2,-1] negation,0.7
-done
-rm[-2]
Then invoke it like this:
$ gmic foo.gmic -foo
Otherwise, you will really have hard times figuring out what are the substitution patterns that will be used by the shell and what are those you have to keep for G’MIC, meaning usually a lot of escapes or single quotes to add to the command line.