Gzip decompress on file with other extension?

Question

Is it possible to use gzip to decompress a gzipped file, without the gz extension, and without moving the file?

Answer 1

You can pass the -S option to use a suffix other than .gz.

gunzip -S .compressed file.compressed

If you want the uncompressed file to have some other name, run

gzip -dc <compressed-file >uncompressed-file
gunzip <compressed-file >uncompressed-file

(these commands are equivalent).

Normally unzipping restores the name and date of the original file (when it was compressed); this doesn't happen with -c.

If you want the compressed file and the uncompressed file to have the same name, you can't do it directly, you need to either rename the compressed file or rename the uncompressed file. In particular, gzip removes and recreates its target file, so if you need to modify the file in place because you don't have write permission in the directory, you need to use -c or redirection.

cp somefile /tmp
gunzip </tmp/somefile >|somefile

Note that gunzip <somefile >somefile will not work, because the gunzip process would see a file truncated to 0 bytes when it starts reading. If you could invoke the truncation, then gunzip would feed back on its own output; either way, this one can't be done in place.

Answer 2

You can, do something like:

gzip -d - < gzippedfilewithnoextention > ungzippedfile

Now you can't do that and uncompress to the same filename. You'll need to rename the uncompressed file afterwards (i.e. you can't in-place uncompress that way).