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compress

file compressionLinux/Unix
The compress command is one of the most frequently used commands in Linux/Unix-like operating systems. compress Compress files using the Lempel-Ziv coding
See ExamplesView Syntax

Quick Reference

Command Name:

compress

Category:

file compression

Platform:

Linux/Unix

Basic Usage:

compress [options] [arguments]

Common Use Cases

  • 1

    File compression

    Compress files to save storage space

  • 2

    Data archiving

    Create compressed archives of files and directories

  • 3

    Storage optimization

    Reduce storage requirements through compression

  • 4

    Data transfer

    Compress files for efficient data transfer

Syntax

compress [-cfvd] [-b bits] [file ...]

Options

Option Description
-c Write to standard output; don't change input files
-d Decompress input instead of compressing it
-f Force compression even if it doesn't save space or the output file already exists
-v Verbose mode; display compression ratio
-b bits Set maximum code size (9 to 16, default is 16)

Examples

How to Use These Examples

The examples below show common ways to use the compress command. Try them in your terminal to see the results. You can copy any example by clicking on the code block.

Basic Examples:

Compress a single file (creates file.Z and removes original)
compress file.txt
Compress a file and keep the original
compress -c file.txt > file.txt.Z
Compress multiple files at once
compress file1.txt file2.txt file3.txt
Decompress a file (alternative to uncompress)
compress -d file.txt.Z

Advanced Examples:

Compress with verbose output showing compression ratio
compress -v largefile.txt
Force compression even if it doesn't save space
compress -f smallfile.txt
Compress with higher compression level (16-bit)
compress -b 16 largefile.txt
Compress and verify data integrity
compress -v file.txt && uncompress -c file.txt.Z | cmp - file.txt
Compress all text files in a directory
find . -name "*.txt" -type f -exec compress {} \;
Compress stdin and send to stdout
cat file.txt | compress -c > file.txt.Z
Compress and create a tar archive
tar cf - directory | compress -c > directory.tar.Z

Try It Yourself

Practice makes perfect! The best way to learn is by trying these examples on your own system with real files.

Understanding Syntax

Pay attention to the syntax coloring: commands, options, and file paths are highlighted differently.

Notes

The compress command reduces the size of files using the Lempel-Ziv coding (LZW). It was one of the first widely used Unix compression utilities but has largely been replaced by more efficient algorithms.

Key points about compress:

  • Creates compressed files with a .Z extension
  • By default, removes the original file after successful compression
  • Typically achieves 50-60% compression for text files
  • Uses the LZW (Lempel-Ziv-Welch) algorithm, which was patented until 2003
  • Has largely been superseded by gzip, bzip2, and xz, which provide better compression ratios

When to use compress:

  • When you need compatibility with very old systems
  • When working with legacy .Z files
  • In scripts that might run on systems without newer compression tools

Comparison with other compression tools:

  • gzip: More efficient than compress, creates .gz files, uses the DEFLATE algorithm
  • bzip2: Better compression than gzip, slower but produces smaller files, creates .bz2 files
  • xz: Best compression among these tools, slowest but smallest files, creates .xz files

Related commands:

  • uncompress: Utility to decompress .Z files (equivalent to compress -d)
  • zcat: View the contents of a .Z file without decompressing it
  • gzip: More modern compression utility that has largely replaced compress

Most modern systems provide compress mainly for backward compatibility, and it's recommended to use newer compression tools like gzip, bzip2, or xz for better compression efficiency.

Common Use Cases

File compression

Compress files to save storage space

Data archiving

Create compressed archives of files and directories

Storage optimization

Reduce storage requirements through compression

Data transfer

Compress files for efficient data transfer

Backup compression

Create compressed backups of important data

Related Commands

These commands are frequently used alongside compress or serve similar purposes:

uncompress
zcat
gzip
gunzip
bzip2
bunzip2
xz
unxz
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Use Cases

1

File compression

Compress files to save storage space

2

Data archiving

Create compressed archives of files and directories

3

Storage optimization

Reduce storage requirements through compression

4

Data transfer

Compress files for efficient data transfer

5

Backup compression

Create compressed backups of important data

Learn By Doing

The best way to learn Linux commands is by practicing. Try out these examples in your terminal to build muscle memory and understand how the compress command works in different scenarios.

See ExamplesTry Lab Exercises
$ compress
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compress - Linux Command Guide