gzip / bzip2 / zip / unzip

Compress with gzip (the original file is removed and replaced by a .gz file).

gzip filename

Extract (decompress) with gzip.

gunzip filename.gz

Use the -k option to compress while keeping the original file.

gzip -k filename

Create a zip archive.

zip archive.zip file-or-directory...

Extract (decompress) a zip archive.

unzip archive.zip

Compress with bzip2.

bzip2 filename

Extract (decompress) with bzip2.

bunzip2 filename.bz2

Command / Option	Description
gzip file	Compresses a file with gzip (replaces the original file).
gzip -d / gunzip	Extracts a gzip file.
gzip -k	Compresses a file while keeping the original.
gzip -1 〜 -9	Sets the compression level (1: fast, low compression; 9: slow, high compression).
gzip -l	Displays information about a compressed file (compression ratio, etc.).
zcat file.gz	Displays the contents of a gzip file without extracting it.
bzip2 file	Compresses a file with bzip2 (higher compression ratio than gzip).
bunzip2 / bzip2 -d	Extracts a bzip2 file.
bzcat file.bz2	Displays the contents of a bzip2 file without extracting it.
zip -r archive.zip directory	Recursively compresses a directory into a zip archive.
zip -e archive.zip file	Creates a password-protected zip archive.
unzip archive.zip	Extracts a zip file.
unzip -l archive.zip	Lists the contents of a zip archive without extracting it.
unzip -d directory	Extracts a zip archive into the specified directory.

Compress a log file with gzip. The original file is removed and replaced by a .gz file.

gzip /var/log/app.log
ls /var/log/app.log*
/var/log/app.log.gz

Compress a file while keeping the original.

gzip -k report.txt
ls report.txt*
report.txt  report.txt.gz

Check information about a compressed file (compression ratio, etc.).

gzip -l app.log.gz
         compressed        uncompressed  ratio uncompressed_name
              45231              234567  80.7% app.log

View the contents without extracting. Using zcat, you can pipe the output to other commands.

zcat /var/log/app.log.gz | grep "ERROR"
2026-03-06 08:15:32 [ERROR] Connection timeout
2026-03-06 09:42:11 [ERROR] File not found

Bundle multiple files into a zip archive.

zip archive.zip file1.txt file2.txt file3.txt
  adding: file1.txt (deflated 62%)
  adding: file2.txt (deflated 58%)
  adding: file3.txt (deflated 71%)

Recursively compress a directory into a zip archive.

zip -r project.zip ./myproject/

List the contents of a zip archive without extracting it.

unzip -l project.zip
Archive:  project.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
     1024  2026-03-06 12:00   myproject/index.php
     2048  2026-03-06 12:00   myproject/css/style.css
---------                     -------
     3072                     2 files

Extract a zip archive into a specific directory.

unzip project.zip -d /tmp/extracted/

Count the number of lines in a gzip-compressed file.

zcat access.log.gz | wc -l
48253

Compression ratio from highest to lowest: xz > bzip2 > gzip; speed is in the reverse order. For everyday tasks like log compression, $ gzip is common. When you need compatibility with Windows, use $ zip.

$ zcat (gzip) and $ bzcat (bzip2) let you read and pipe compressed file contents without extracting them. To archive entire directories, it is standard practice to combine these commands with tar.