A command that spies on a binary by being run in its place, calling the original and forking all input and output to logfiles as well as the called subprocess

fake.sh

#!/bin/bash

OUTPUT=$(mktemp -d --tmpdir=/tmp "$(date -Iseconds).$(basename $0).XXXXXXX")
echo "$@" > "${OUTPUT}/cmdline"
env > "${OUTPUT}/env"
cat - \
  | tee "${OUTPUT}/input" \
  | /usr/cni/bin/$(basename $0) $@ \
  | tee "${OUTPUT}/output"
cd "${OUTPUT}"
cat cmdline \
    <(echo ===) \
    env \
    <(echo ===) \
    input \
    <(echo ===) \
    output \
  > summary

Currently only works with binaries in /usr/cin/bin