Choosing a Compressor

gzip vs bzip2 vs xz vs zip

They all shrink files, trading speed against ratio (how small).

Tool	tar flag	Speed	Ratio	Use when
`gzip`	`z`	⚡ Fast	Good	The safe default
`bzip2`	`j`	Slow	Better	Space matters more than time
`xz`	`J`	Slowest	Best	Archiving big data long-term
`zip`	-	Fast	Good	Sharing with Windows users

$ tar -czf a.tar.gz  dir/     # gzip  (z)
$ tar -cJf a.tar.xz  dir/     # xz    (J) - smallest
$ zip -r a.zip dir/           # zip   (cross-platform)
$ unzip a.zip

Standalone (on a single file): gzip file → file.gz, and gunzip file.gz to reverse.

Tip: Rule of thumb: gzip for everyday (fast, universal), xz when you want it as small as possible and don't mind waiting, zip when a Windows user is on the other end.

Analogy: Speed vs ratio is like packing a bag: throw everything in fast (gzip), or fold meticulously so more fits but it takes longer (xz).