`pipe` command for post-processing output

[deliciouslytyped]

Information from remake's debugger REPL can be rather verbose sometimes; it could be nice to have some post-processing capability, such as running grep on output. The shell command exists, but it seems kind of useless in isolation?

https://stackoverflow.com/questions/15960180/how-to-grep-on-gdb-print lists some examples on how this is handled in GDB; and it seems relatively recent GDB has a pipe command.