Linux compression and archiving

Compression

Compact format: GZ, bz2, XZ, zip, Z, and so on.

Compression algorithm: The algorithm is different, the compression ratio is also different.

Comperss:filename.z low Compression ratio.

Uncompress

Gzip

Filename.gz

Only files can be compressed.

#gzip [OPTION] FILENAME compression is complete and the source file is deleted.

[OPTION]

-D unzip the file, equivalent to Gunzip.

-num compression ratio. 1-9, default is 6.

#gunzip filename.gz The source file is deleted when the decompression is complete.

#zcat FILENAME to view the contents of a text file without being pressed.

bzip2;

A compression tool that has a greater compression ratio than gzip. The source file is also deleted when the decompression is complete. Only files can be compressed.

filename.bz2

#bzip2 [OPTION] FILENAME

-D unzip the file, equivalent to BUNZIP2.

-K--keep Keep the source file when compressing.

-num compression ratio. 1-9, default is 6.

#bunzip2 filename.bz2

#bzcat filename.bz2 to view the contents of a text file without being pressed.

Xz

Filename.xz

#xz [OPTION] FILENAME

The source file is deleted when the compression is complete. Only files can be compressed.

[OPTION]

-D unzip the file.

-num compression ratio. 1-9, default is 6.

-K--keep Keep the source file when compressing.

#unxz filename.xz The source file is deleted when the decompression is complete.

#xzcat FILENAME to view the contents of a text file without being pressed.

#xzdec usage is similar to XZ.

Zip:

The compression ratio is small, but the files within the directory and directory can be compressed. is both compressed and archived, and the source files are not deleted after compression.

#zip [OPTION] filename.zip FILE1 FILE2 ...

#unzip Filename.zip

Archive (archive):

The archive itself does not imply this compression.

Filename.tar

Tar

#tar [OPTION]

-C Create an archive file.

The-F Filename.tar Operation's archive file is named filename.

-X expands the archive.

--xattrs preserves extended attribute information for files when archiving.

-T does not expand the archive to view the contents of the archive file.

-V displays the procedure.

-Z Call gzip

-j Call bzip2

-j Call XZ

For example:

#tar-JCF abc.tar.xz Test*.txt

#tar-JCF abc.tar.bz2

#tar-ZCF abc.tar.gz

#tar-ZXF abc.tar.gz

#tar-JXF ABC.TAR.BZP2

#tar-JXF Abc.tar.xz

#tar-xf Abc.tar.xz tar automatically determines the compression software, so the-J|J|Z option can be ignored.

Cpio

Copy files into archives.

Practice:

1. Write a script that lets the user enter several files from the keyboard, and the script can compress several files into a single file.

#!/bin/bash

Read-p "Three files:" FILE1 FILE2 FILE3

Read-p "dir" dir

Read-p "COM Type:[gzip|bzip2|xz]:" $TYPE

Case $TYPE in

Gzip

TAR-ZCF [$DIR].tar.gz $FILE 1 $FILE 2 $FILE 3

BZIP2)

TAR-JCF [$DIR].tar.bz2 $FILE 1 $FILE 2 $FILE 3

Xz

TAR-JCF [$DIR].tar.xz $FILE 1 $FILE 2 $FILE 3

*)

echo "unkown!"

Exit 9

Esac

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Linux compression and archiving