If you are using latest (and greatest) vi/vim then it can open gzipped files (those with extension .gz) automagically, but it’s not so easy if you must use some old/outdated system where is also old vi/vim.
So, what to do? Gunzipping is sometimes impossible (no gunzip? not enough free space? readonly system? too many files to just search through…). Use zcat!
$ zcat filename.gz | vi -
That’s not all!
gzip package (on Gentoo : app-arch/gzip) contains many more commands useful with .gz files, for example:
* zcmp – binary-compare two gzipped files
* zdiff – compare two gzipped files
* zgrep, zegrep, zfgrep – grep in gzipped files
* zless, zmore – do less and more on gzipped files