largs

#!/usr/bin/env bash
#
# Requirements:
#   - sed
#   - walk-run (included in the bash-stdops project)
#
# Author: James Cherti
# URL: https://github.com/jamescherti/bash-stdops
#
# Description:
# ------------
# This script reads from standard input and executes a command for each line,
# replacing `{}` with the content read from stdin. It expects `{}` to be passed
# as one of the arguments and will fail if `{}` is not provided.
#
# This script is an alternative to xargs.
#
# { echo "file1"; echo "file2"; } | largs ls {}
#
# License:
# --------
# Copyright (C) 2012-2024 James Cherti
#
# Distributed under terms of the GNU General Public License version 3.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#

set -euf -o pipefail

main() {
  local errno=0

  if [[ $# -lt 1 ]]; then
    echo "Executes a command for each line in the standard input, "
    echo "replacing '{}' with the line content."
    echo
    echo "Usage: $0 <command> [args] {}" >&2
    echo
    echo "Example:"
    echo "  { echo 'file1'; echo 'file2'; } | largs ls {}"
    exit 1
  fi

  local cmd
  cmd="$1"
  if ! command -v "$cmd" &>/dev/null; then
    echo "Error: command not found: $cmd" >&2
    exit 1
  fi

  # Set IFS to newline to properly handle lines with spaces
  IFS=$'\n'

  local line

  while read -r line; do
    local brackets_found=0
    local cmd
    cmd=()
    for arg in "$@"; do
      if [[ $arg = '{}' ]]; then
        cmd+=("$line")
        brackets_found=1
      else
        cmd+=("$arg")
      fi
    done

    if [[ $brackets_found -eq 0 ]]; then
      echo "Error: the brackets '{}' are required.'" >&2
      exit 1
    fi

    # echo "[RUN]" "${cmd[@]}" >&2
    "${cmd[@]}" || errno=1
  done

  exit "$errno"
}

main "$@"