Pipe & Arguments

Test case

foo() {
  if [ -t 0 ]; then
    echo "Called normally"
    echo "Received arg: $1"
  else
    echo.green "Called from a pipeline"

    while IFS= read -r line; do
      echo "Processing piped input: $line"
    done
  fi
}
export -f foo


main() {
  echo "Calling foo() normally"
  foo "bar"
  echo "--------------------------------------------------------------------------------"
  echo "Calling foo() from a pipeline"
  echo "bar" | foo
}

main "${@}" || exit 1

Output:

Calling foo() normally
Called normally
Received arg: bar
--------------------------------------------------------------------------------
Calling foo() from a pipeline
Called from a pipeline
Processing piped input: bar

real	0m0.016s
user	0m0.013s
sys	0m0.004s

# shellcheck disable=SC2120
bar(){
  if [ -t 0 ]; then
    echo "BAR Called normally: $*"
  else
    echo "BAR Called from a pipeline"

    while IFS= read -r line; do
      echo.bold "BAR Processing piped input: $line"
      sleep 2
    done
  fi
}

foo() {
  if [ -t 0 ]; then
    echo "${*:?}" | jq -c | bar
  else
    jq -c | bar
  fi
}
export -f foo

main() {
  echo.green "$(date.now)"
  echo.jsonl | jq | foo
  echo.green "$(date.now)"
  foo '{"hi":"there"}'
}

main "${@}" || exit 1

Output:

2023-12-14T21-17-51PST
BAR Called from a pipeline
BAR Processing piped input: {"title":"title-val-1","note":"note-val-1"}
BAR Processing piped input: {"title":"title-val-2","note":"note-val-2"}
BAR Processing piped input: {"title":"title-val-3","note":"note-val-3"}
2023-12-14T21-17-57PST
BAR Called from a pipeline
BAR Processing piped input: {"hi":"there"}