gzip and gunzip are GNU file compression and decompression utilities. Usually, files that have been compressed by gzip will have a .gz extension. However, sometimes you may see a file that has a .tgz extension. This is a TAR file that has been compressed by gzip. The .tgz extension is a shorthand version for the .tar.gz extension.
This type of file must be uncompressed with gunzip before it can be untarred. However, there is a way to use the tar command to uncompress the file and untar it at the same time. For more information, see the tar: Tape Archive Files guide.
Uncompressing a gzip File Using gunzip
To uncompress a gzip file, execute the following command:
gunzip filename.txt.gz (where filename.txt.gz is the name of the file you wish to uncompress)
The result of this operation is a file called filename.txt. By default, gunzip will delete the filename.txt.gz file.
Compressing a File Using gzip
To compress a file using gzip, execute the following command:
gzip filename.txt (where filename.txt is the name of the file you wish to compress)
The result of this operation is a file called filename.txt.gz. By default, gzip will delete the filename.txt file.