CIS241

System-Level Programming and Utilities

Compression

Erik Fredericks, frederer@gvsu.edu
Fall 2025

Based on material provided by Erin Carrier, Austin Ferguson, and Katherine Bowers

How to squish (compress) a file

Windows compatible (by default) ... usually

zip file.zip files_to_compress

unzip file.zip

• Note, not all distributions come with zip/unzip installed!

Compressing - Linux edition

gzip - fastest

• gzip file
  • gunzip file.gz

bz2 - old standard, better compression

• bzip2 file
• bunzip2 file.bz2

xz - new standard, may not be installed

• xz file
• unxz file.xz

Compressing - directories!

Zip can handle by default

• Others work on single files only!

So, let's tar it

• tar -cvf name.tar file1 file2
  • Files can be directories here!

Can extract:

• tar -xvf name.tar

Or view its table of contents:

• tar -tvf name.tar

But more commonly, tar + compression!

Let's automatically compress/decompress!

• -z for gzip
• -j for bzip2
• -J for xz

Ex (compress): tar -zcvf name.tar.gz dir1 dir2 file1

• Note: toss on the common extension to tell others what type of compression is used

Ex (decompress): tar -zxvf name.tar.gz