#!/usr/bin/env bash
# each.sh — run a command for each item. Replaces v1 `each`.
#
# Two input modes:
#   each.sh <CMD> <ARG1> [ARG2 ... ARGN]   — args as items
#   <stream> | each.sh <CMD>               — stdin lines as items (one per line)
#
# The literal token {} in CMD, if present, gets replaced with the current item.
# Otherwise the item is appended as the last arg.
#
# Examples:
#   each.sh 'echo got:' /etc/hosts /etc/passwd
#   tbn adt | awk 'NR>1{print $2}' | each.sh 'echo route_test for' {}
#   nc-find.sh --process codametrix --format tsv \
#     | awk -F'\t' 'NR>1{print $2}' \
#     | each.sh 'lib/nc-msgs.sh' {} '--limit' '1' '--format' 'count'
#
# Each invocation is a separate process; failures are not aggregated. To
# stop on first error, prepend `set -e` in your own wrapper.
set -o pipefail

usage() { sed -n '2,20p' "$0"; exit 0; }
[ $# -ge 1 ] || usage
case "$1" in -h|--help) usage ;; esac

CMD="$1"; shift

run_one() {
  local item="$1"
  if [[ "$CMD" == *"{}"* ]]; then
    eval "${CMD//\{\}/\"\$item\"}"
  else
    # Append item as last arg
    eval "$CMD \"\$item\""
  fi
}

if [ $# -gt 0 ]; then
  for item in "$@"; do run_one "$item"; done
else
  while IFS= read -r item; do
    [ -z "$item" ] && continue
    run_one "$item"
  done
fi