How to trace calls using GDB

Vector's command line tools do not include a ptrace (as far as I can see). This can be emulated with GDB. Here is an example tracing a write() call.

1. Start gdb and attach to the process of interest.
2. Add the following scripted breakpoints:

    break write
    command
    silent
    printf "%d bytes\n", $r2
    x/80c $r1
    continue
    end

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