Radare scripts are just unidirectional scripts that are parsed in the core from a file or from the output of a program.
This methodology is quite used for automatizing simple tasks or for data adquisition.
[0x00000000]> !cat binpatch.rsc
wx 90 90 @ 0x300
[0x00000000]> . file ; interpret this file
You can obviously do the same by interpreting the output of a command:
[0x00000000]> .! rsc syms-dbg-flag ${FILE}