Archive, compress, unpack, and uncompress files using tar, gzip, and bzip2

Archive, compress, unpack, and uncompress files using tar, gzip, and bzip2

In this section, will learn about archive and file compression. The tar is file/directory archiver, we can put alot of files and directory into one archive file. Then we need file compressor to decrease its size, the two toos - gzip and bzip2 is a file compressor. We cannot compress directory with these tools, so we need to create an archive then compress them if we have many files, otherwise we can only compress each files separatelly with the tools.

Archive

I have created 9 empty files, each file size is 10MB. Files were created and put into tmpfiles directory with this one-line command:

[root@bali1 targzipbzip2]# for i in {1..9};do dd if=/dev/zero of=./tmpfiles/imgfile$i.img bs=1024 count=0 seek=$[1024*10];done

[root@bali1 targzipbzip2]# ls -lh ./tmpfiles/
total 0
-rw-r--r--. 1 root root 10M Feb 18 05:13 imgfile1.img
-rw-r--r--. 1 root root 10M Feb 18 05:13 imgfile2.img
-rw-r--r--. 1 root root 10M Feb 18 05:13 imgfile3.img
-rw-r--r--. 1 root root 10M Feb 18 05:13 imgfile4.img
-rw-r--r--. 1 root root 10M Feb 18 05:13 imgfile5.img
-rw-r--r--. 1 root root 10M Feb 18 05:13 imgfile6.img
-rw-r--r--. 1 root root 10M Feb 18 05:13 imgfile7.img
-rw-r--r--. 1 root root 10M Feb 18 05:13 imgfile8.img
-rw-r--r--. 1 root root 10M Feb 18 05:13 imgfile9.img

We can create an archive of a file, several files, or even archive of a directory or folder

[root@bali1 targzipbzip2]# tar -cvf imgfile.tar ./tmpfiles/imgfile1.img 
./tmpfiles/imgfile1.img
[root@bali1 targzipbzip2]# ls -lh imgfile.tar 
-rw-r--r--. 1 root root 11M Feb 18 05:41 imgfile.tar

[root@bali1 targzipbzip2]# tar -cvf imgfiles.tar ./tmpfiles/imgfile1.img ./tmpfiles/imgfile2.img ./tmpfiles/imgfile3.img 
./tmpfiles/imgfile1.img
./tmpfiles/imgfile2.img
./tmpfiles/imgfile3.img
[root@bali1 targzipbzip2]# ls -lh imgfiles.tar 
-rw-r--r--. 1 root root 31M Feb 18 05:42 imgfiles.tar

[root@bali1 targzipbzip2]# tar -cvf imgfiles-all.tar ./tmpfiles
./tmpfiles/
./tmpfiles/imgfile1.img
./tmpfiles/imgfile2.img
./tmpfiles/imgfile3.img
./tmpfiles/imgfile4.img
./tmpfiles/imgfile5.img
./tmpfiles/imgfile6.img
./tmpfiles/imgfile7.img
./tmpfiles/imgfile8.img
./tmpfiles/imgfile9.img
[root@bali1 targzipbzip2]# ls -lh imgfiles-all.tar 
-rw-r--r--. 1 root root 91M Feb 18 05:44 imgfiles-all.tar

Compress

We can compress the archive file with gzip or bzip2

[root@bali1 targzipbzip2]# gzip imgfile.tar 
[root@bali1 targzipbzip2]# ls -lh imgfile.tar.gz 
-rw-r--r--. 1 root root 11K Feb 18 05:41 imgfile.tar.gz

[root@bali1 targzipbzip2]# bzip2 imgfiles.tar 
[root@bali1 targzipbzip2]# ls -lh imgfiles.tar.bz2 
-rw-r--r--. 1 root root 173 Feb 18 05:42 imgfiles.tar.bz2

Uncompress

To uncompress we use option -d on both tools

[root@bali1 targzipbzip2]# gzip -d imgfile.tar.gz 
[root@bali1 targzipbzip2]# ls -lh imgfile.tar 
-rw-r--r--. 1 root root 11M Feb 18 05:41 imgfile.tar
[root@bali1 targzipbzip2]# bzip2 -d imgfiles.tar.bz2 
[root@bali1 targzipbzip2]# ls -lh imgfiles.tar 
-rw-r--r--. 1 root root 31M Feb 18 05:42 imgfiles.tar

Unpack

Unpack will overwrite any existing files if available, except we use -k option to keep the existing one. We could also define direcory location with optin -C

[root@bali1 targzipbzip2]# tar -xvf imgfile.tar 
./tmpfiles/imgfile1.img

[root@bali1 targzipbzip2]# tar -xvf imgfiles.tar 
./tmpfiles/imgfile1.img
./tmpfiles/imgfile2.img
./tmpfiles/imgfile3.img

[root@bali1 targzipbzip2]# ls -lh ./tmpfiles/imgfile[123].img
-rw-r--r--. 1 root root 10M Feb 18 05:13 ./tmpfiles/imgfile1.img
-rw-r--r--. 1 root root 10M Feb 18 05:13 ./tmpfiles/imgfile2.img
-rw-r--r--. 1 root root 10M Feb 18 05:13 ./tmpfiles/imgfile3.img

Putting all together

We can do the whole process with tar command and several compression formats available

[root@bali1 targzipbzip2]# tar -czvf tmpfiles.tar.gz ./tmpfiles
./tmpfiles/
./tmpfiles/imgfile1.img
./tmpfiles/imgfile2.img
./tmpfiles/imgfile3.img
./tmpfiles/imgfile4.img
./tmpfiles/imgfile5.img
./tmpfiles/imgfile6.img
./tmpfiles/imgfile7.img
./tmpfiles/imgfile8.img
./tmpfiles/imgfile9.img
[root@bali1 targzipbzip2]# ls -lh tmpfiles.tar.gz 
-rw-r--r--. 1 root root 91K Feb 18 06:23 tmpfiles.tar.gz

[root@bali1 targzipbzip2]# tar -cjvf tmpfiles.tar.bz2 ./tmpfiles
./tmpfiles/
./tmpfiles/imgfile1.img
./tmpfiles/imgfile2.img
./tmpfiles/imgfile3.img
./tmpfiles/imgfile4.img
./tmpfiles/imgfile5.img
./tmpfiles/imgfile6.img
./tmpfiles/imgfile7.img
./tmpfiles/imgfile8.img
./tmpfiles/imgfile9.img
[root@bali1 targzipbzip2]# ls -lh tmpfiles.tar.bz2 
-rw-r--r--. 1 root root 419 Feb 18 06:24 tmpfiles.tar.bz2

[root@bali1 targzipbzip2]# tar -cJvf tmpfiles.tar.xz ./tmpfiles
./tmpfiles/
./tmpfiles/imgfile1.img
./tmpfiles/imgfile2.img
./tmpfiles/imgfile3.img
./tmpfiles/imgfile4.img
./tmpfiles/imgfile5.img
./tmpfiles/imgfile6.img
./tmpfiles/imgfile7.img
./tmpfiles/imgfile8.img
./tmpfiles/imgfile9.img
[root@bali1 targzipbzip2]# ls -lh tmpfiles.tar.xz 
-rw-r--r--. 1 root root 15K Feb 18 06:25 tmpfiles.tar.xz

Extract and overwrite the files in loop

[root@bali1 targzipbzip2]# ls *tar*
tmpfiles.tar.bz2  tmpfiles.tar.gz  tmpfiles.tar.xz
[root@bali1 targzipbzip2]# ls *tar*|while read f;do tar -xvf $f;done
./tmpfiles/
./tmpfiles/imgfile1.img
./tmpfiles/imgfile2.img
./tmpfiles/imgfile3.img
./tmpfiles/imgfile4.img
./tmpfiles/imgfile5.img
./tmpfiles/imgfile6.img
./tmpfiles/imgfile7.img
./tmpfiles/imgfile8.img
./tmpfiles/imgfile9.img
./tmpfiles/
./tmpfiles/imgfile1.img
./tmpfiles/imgfile2.img
./tmpfiles/imgfile3.img
./tmpfiles/imgfile4.img
./tmpfiles/imgfile5.img
./tmpfiles/imgfile6.img
./tmpfiles/imgfile7.img
./tmpfiles/imgfile8.img
./tmpfiles/imgfile9.img
./tmpfiles/
./tmpfiles/imgfile1.img
./tmpfiles/imgfile2.img
./tmpfiles/imgfile3.img
./tmpfiles/imgfile4.img
./tmpfiles/imgfile5.img
./tmpfiles/imgfile6.img
./tmpfiles/imgfile7.img
./tmpfiles/imgfile8.img
./tmpfiles/imgfile9.img

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This material is refers to the rhca objectives