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📛 NAME

comm - compare two sorted files line by line

🚀 Quick Reference

Use Case	Command	Description
🔍 Show all differences	comm file1 file2	Three-column output: unique to file1, unique to file2, common lines
🤝 Show only common lines	comm -12 file1 file2	Suppress columns 1 and 2
📄 Show lines unique to file1	comm -23 file1 file2	Suppress columns 2 and 3
📄 Show lines unique to file2	comm -13 file1 file2	Suppress columns 1 and 3
🔄 Show lines in file1 not in file2 and vice versa	comm -3 file1 file2	Suppress common lines

📖 SYNOPSIS

comm [OPTION]... FILE1 FILE2

📝 DESCRIPTION

Compare sorted files FILE1 and FILE2 line by line.

When FILE1 or FILE2 (not both) is -, read standard input.

With no options, produce three-column output. Column one contains lines unique to FILE1, column two contains lines unique to FILE2, and column three contains lines common to both files.

⚙️ OPTIONS

• -1 – 🚫 Suppress column 1 (lines unique to FILE1)
• -2 – 🚫 Suppress column 2 (lines unique to FILE2)
• -3 – 🚫 Suppress column 3 (lines that appear in both files)
• --check-order – ✅ Check that the input is correctly sorted, even if all input lines are pairable
• --nocheck-order – ❌ Do not check that the input is correctly sorted
• --output-delimiter=STR – 🔀 Separate columns with STR
• --total – 📊 Output a summary
• -z, --zero-terminated – 🔚 Line delimiter is NUL, not newline
• --help – ℹ️ Display this help and exit
• --version – ℹ️ Output version information and exit

Note: comparisons honor the rules specified by LC_COLLATE.

💡 EXAMPLES

comm -12 file1 file2

👉 Print only lines present in both file1 and file2.

comm -3 file1 file2

👉 Print lines in file1 not in file2, and vice versa.

👤 AUTHOR

Written by Richard M. Stallman and David MacKenzie.

🐛 REPORTING BUGS

GNU coreutils online help: https://www.gnu.org/software/coreutils/
Report any translation bugs to https://translationproject.org/team/

©️ COPYRIGHT

Copyright © 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later https://gnu.org/licenses/gpl.html.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

🔗 SEE ALSO

join(1), uniq(1)

Full documentation https://www.gnu.org/software/coreutils/comm
or available locally via: info '(coreutils) comm invocation'

📛 NAME 🚀 Quick Reference 📖 SYNOPSIS 📝 DESCRIPTION ⚙️ OPTIONS 💡 EXAMPLES 👤 AUTHOR 🐛 REPORTING BUGS ©️ COPYRIGHT 🔗 SEE ALSO