gzip

Additional Notes

gzip compresses individual files using the gzip format and usually replaces each input file with a .gz file. It is common for logs, tar archives, HTTP content, and Unix pipelines.

gzip is not a multi-file archive tool by itself. To package a directory and compress it, combine tar with gzip, such as tar -czf backup.tar.gz directory/.

Syntax

gzip [options] file...
gunzip [options] file.gz...

Parameters

• file: File to compress. By default, the original file is replaced with file.gz.
• file.gz: Compressed file to decompress.
• options: Compression level, retention, recursion, and output behavior flags.

Common Options

• -d: Decompress. Same basic role as gunzip.
• -k: Keep the original file.
• -r: Recursively compress files inside directories.
• -1: Fastest compression, larger output.
• -9: Best compression, slower output.
• -c: Write output to standard output instead of replacing files.
• -l: List compressed and uncompressed size information.
• -t: Test compressed file integrity.

Examples

gzip access.log

Compress access.log into access.log.gz and remove the original.

gzip -k access.log

Compress the file while keeping the original.

gzip -9 large.log

Use maximum compression.

gzip -dc access.log.gz | less

View decompressed content without writing a new file.

gzip -t archive.gz

Check that a gzip file can be decompressed.

Practical Notes

• Use tar -czf for directories or multiple files.
• Use zcat, zgrep, and zless for reading compressed text without manual decompression.
• Remember that default gzip file removes the original file. Add -k when that is not desired.