xargs - macOS

Overview

xargs is a powerful command-line utility that constructs and executes command-lines from standard input. It’s commonly used to split up large lists of arguments into smaller batches, making it easier to process them with other commands.

Syntax

xargs [-0] [-a file] [-d delim] [-e eofstr] [-i replace-str] [-l max-args] [-n max-args] [-p] [-s max-chars] [--null] [--verbose] [--replace] [--eof-str] [--exit] [--delimiter] [--max-args] [--max-chars] [--interactive] [--line-buffered] [--pending] [--show-limits] [--arg-file] [command [initial-arguments]]]

Options/Flags

  • -0, --null: Use null characters as delimiters instead of whitespace.
  • -a file, --arg-file: Read arguments from the specified file.
  • -d delim, --delimiter: Specify a custom delimiter. Default is whitespace.
  • -e eofstr, --eof-str: Append eofstr to the end of the command line.
  • -i replace-str, --replace: Replace replace-str in the command line with each argument.
  • -l max-args, --max-args: Limit the number of arguments per command line.
  • -n max-args, --max-chars: Limit the number of characters per command line.
  • -p, --interactive: Prompt for confirmation before executing commands.
  • -s max-chars, --max-chars: Limit the total character length of the command line.

Examples

Example 1: Execute rm with a list of files

find . -name "*.txt" | xargs rm

Example 2: Use xargs with the -n option to process 5 files at a time

find . -name "*.txt" | xargs -n 5 rm

Example 3: Replace {} with the first argument in the command line

echo "Delete file: {}" | xargs -i /bin/rm {}

Common Issues

  • Error: Argument list too long: Use the -n or -s options to limit the number of arguments or characters per command line.
  • Error: No command specified: Provide a command after the options.

Integration

  • Chaining with find: Use find to generate a list of arguments (e.g., file paths), then pipe the output to xargs to execute commands on them.
  • Combining with parallel: Use xargs to create multiple commands from a single list of arguments, then execute them in parallel with parallel.
  • find: Generates a list of files or directories.
  • awk: A text processing tool.
  • parallel: Executes multiple commands in parallel.