The push keyword is used to push STREAMS modules onto the stream designated by fd. See the doconfig(3NSL) man page.
push module1[, module2, module3, ...]
module1 is the name of the first module to be pushed, module2 is the name of the second module to be pushed, and so on. The command fails if any of the named modules cannot be pushed. If a module cannot be pushed, the subsequent modules on the same command line are ignored and modules that have already been pushed are popped.