Compressed files use less disk space and download faster than large,
uncompressed files. You can compress Linux files with the open-source
compression tool Gzip or with Zip, which is recognized by most operating systems.
By convention, compressed files are given the extension .gz. The command Gzip creates a
compressed file ending with .gz;
Gunzip extracts the compressed files and
removes the .gz file.
To compress a file, at a shell prompt, type the following command:
The file will be compressed and saved as
filename.ext.gz.
To expand a compressed file, type:
The filename.ext.gz is deleted and replaced with
filename.ext.
If you exchange files with non-Linux users, you may want to use
zip to avoid compatibility problems. Red Hat Linux can
easily open zip or gzip files, but non-Linux operating systems may
have problems with gzip files.
To compress a file with zip, type the following:
zip -r filename.zip files |
In this example, filename represents the file you
are creating and files represents the files you
want to put in the new file:
To extract the contents of a zip file, type:
You can zip or gzip multiple files at the same time. List the files
with a space between each one.
gzip filename.gz file1 file2 file3 /user/work/school |
The above command will compress file1,
file2, file3, and the
contents of the /user/work/school directory and
put them in filename.gz.
Tar files place several files or the contents of a directory or directories
in one file. This is a good way to create backups and
archives. Usually, tar files end with the .tar
extension.
To create a tar file, type:
tar -cvf filename.tar files/directories |
In this example, filename.tar represents the file
you are creating and files/directories represents
the files or directories you want to put in the new file.
You can use absolute or relative pathnames for these files and
directories (for more on pathnames, see the section called Changing Directories with cd in Chapter 10). Separate the names of files and
directories with a space.
The following input would create a tar file using absolute pathnames:
tar -cvf foo.tar /home/mine/work /home/mine/school |
The above command would place all the files in the
/work subdirectory and the /school subdirectory
in a new file called foo.tar in the current
working directory.
The command tar -cvf foo.tar file1.txt file2.txt
file3.txt would place file1.txt,
file2.txt and file3.txt in
a new file called foo.tar.
To list the contents of a tar file, type:
To extract the contents of a tar file, type:
This command does not remove the .tar file, but
it places copies of the .tar contents in the
current working directory.
The tar command does not compress
files automatically. You can compress tar files with:
Compressed tar files are conventionally given the extension
.tgz and are compressed with gzip.
To expand a compressed tar file type:
