TAR is a linux command that allows you to archive entire files & directories into one file that can be moved quickly to another location. On paper it creates a tape archive (TARBALL) of your files, allowing you to extract them later on and compress their contents via BZIP.
Creating a .TAR
tar -cvvf backup.tar work
...creates a tar file named work.tar which contains everything in work directory and recursively everything beyond
tar -cjvf backup.tbz work
...adding -j enables tar to compress files & directories with bzip, backing up everything in the work directory and everything beyond. note the different extension used -> .tbz denoting it's a compressed archive
Extracting a .TAR
tar -xvvf backup.tar
...extracts / untar's everything from the work.tar tarball inside the directory your in
If bzipped, extract with...
tar -xjvf backup.tgz
Or gzipped, extract with...
tar -xcvf backup.tar.gz
GZip is essentially a free version of winzip without the you-gotta-pay-for-it stamp. Now used on it's own it works on single files turning them into gzipped .gz files, with TAR and it allows you to gzip tons of files (see examples above).
To gzip a file do...
...this gzips it to myfile.gz
To extract the gzipped file do...
Archive & Compress directory I'm in
tar -zcvf backup.tgz .
...Then Extract it
tar -xzvf backup.tgz