You need to use tar command as follows (syntax of tar command):
tar -zcvf archive-name.tar.gz directory-name
Where,

• -z: Compress archive using gzip program
• -c: Create archive
• -v: Verbose i.e display progress while creating archive
• -f: Archive File name

For example, you have directory called /home/jerry/prog and you would like to compress this directory then you can type tar command as follows:

$ tar -zcvf prog-1-jan-2005.tar.gz /home/jerry/prog