"Posting" escape characters

I’m interested in posting text in color when sclang is run from the command line. There was a similar question about posting in color in the post window, but this is about running sclang on its own.

I was trying to “post” commands with appropriate escape characters, e.g.:

27.asAscii ++ "[32mgreen".postln;
"\\" ++ 27.asAscii ++ "[32mgreen".postln;

When running sclang with this file from the command line, none of the lines resulted in colored posting.
Posting through echo works (e.g. "echo \"\\x1b[32mgreen\"".unixCmd;), but this seems to break when posting hundreds of lines in close succession.

I have a workaround writing a string to a file and then piping it to echo, but that’s not ideal. Is there really no way to “post” escape codes from sclang?

For reference: it was helpful for me to see this gist listing escape sequences in various formats.