find_pair - Linux


find_pair searches through a collection of elements and identifies pairs of them that meet a specified condition. It is particularly useful for performing pattern matching, finding duplicate items, or identifying related data points.


find_pair [--element-separator=<char>] [--line-separator=<char>] [--condition=<condition>] <input-file>


  • –element-separator=: Specify the character that separates elements within a line. Default: space.
  • –line-separator=: Specify the character that separates lines in the input file. Default: newline.
  • –condition=: Specify a logical expression to determine if a pair of elements meets the matching condition. Default: equality of elements.


  • Find pairs of duplicate lines in a file:
find_pair /path/to/file.txt
  • Find pairs of strings that differ by a single character:
find_pair --condition='len(a) == len(b) and sum(a != b) == 1' input.txt
  • Find pairs of lines containing specific keywords:
find_pair --condition='"keyword1" in a and "keyword2" in b' file1.txt file2.txt

Common Issues

  • Input files should be consistent and follow the specified separators for correct parsing.
  • The condition expression must be valid Python syntax.


find_pair can be integrated with other Linux commands for advanced tasks:

  • Find duplicate files: find_pair --element-separator='\n' /path/to/dir | sort | uniq
  • Identify pairs of similar images: find_pair --condition='compare_images(a, b) > 0.9'

Related Commands

  • grep: Search for text patterns.
  • diff: Compare two files line by line.
  • uniq: Remove duplicate lines from a file.