compress – Compress data files using Lempel-Ziv encoding

The compress command is used to compress data files using the Lempel-Ziv encoding algorithm. This command is often used to reduce the size of files and save disk space. The compressed file is saved with a .Z extension.


The basic syntax for the compress command is as follows:

compress [options] file

where file is the name of the file that you want to compress.

For example, to compress a file called example.txt, you would run the following command:

compress example.txt

To decompress a compressed file, you can use the uncompress command:

uncompress example.txt.Z

Use cases

  • Compressing large log files to save disk space
  • Compressing backups before storing them
  • Compressing email attachments before sending them


The following table lists the available options for the compress command:

Option Description
-c Write output to standard output and do not change the input file.
-f Force compression even if the compressed file already exists.
-r Recursively compress files in subdirectories.
-v Verbose mode. Print the name of each file as it is compressed.
-V Print version information and exit.
--help Print help message and exit.

Troubleshooting tips

  • If you receive an error message stating that the file is already compressed, use the -f option to force compression.
  • If the compressed file is not smaller than the original file, it may not be worth compressing the file.


  • The Lempel-Ziv encoding algorithm used by the compress command is not as efficient as modern compression algorithms like gzip or bzip2.