Linux file archiving and compression (Learn note eight)

I. Archiving and compression

• Compression Command tool: GZIP,BZIP2
• Archive Command tool: Tar

Second, compression

2.1. Gzip

Gzip is a standard, widely-used file compression and decompression utility. Gzip allows file to be collocated. With gzip compressed files, you can get tarball packaged files in the format "*.tar.gz" or "*.tgz".

Gzip Options

• –stdout: Writes the output to the standard output device.
• –to-stdout: Writes the output to the standard output device.
• –decompress: Unzip the file.
• –uncompress: Unzip the file.
• -D: Unzip the file.
• -F: Forced compression/decompression.

2.2, BZIP2

BZIP2 will get a higher compression rate than gzip

Command: bzip2 [options] [filename] parameter-C sends the result of the compression/decompression to standard output-D to extract the specified target file. -Z enforces compression, whether compression command bzip2 or decompression command bunzip.-k the original file during compression or decompression. -F forced override. -T checks the integrity of the specified compressed file, but does not decompress it. -S reduces memory utilization. -V Displays the compression ratio of the compressed file. --processing of files beginning with "-" such as: bzip2---filename--help display Help-num to adjust the compression speed with the specified number-1 or--fast for the fastest compression (low compression ratio), 9 or-best, which indicates the slowest (high compression ratio), the system defaults to 6. Third, archiving

An archive file is a compressed file that consists of one or more computer files and metadata

3.1 Features of the archive

• Data compression
• Encryption
• File collocated
• Automatic decompression
• Automatic installation
• Source volume and media information
• File spanning
• Checksum
• Directory structure Information
• Other metadata (data about the data)
• Error discovery

3.2. Tar command:

Tar is the standard Unix/linux Archiving application tool. In the early stages, it used to be a tape archive software that later evolved into a generic archive package capable of processing various types of archive files. Tar can accept many archive filters with options.

tar option -A: Adds a tar file to the end of an existing archive. -C: Create a new archive file. -D: Compare archives using the specified file system. -J: Archive with bZIP compression. -R: Adds the file to the end of the existing archive. -T: Lists the contents of an existing archive. -u: Update archive. -x: Unzip the file from the existing archive. -Z: Archive with gzip compression. –delete: Delete files from an existing archive. 

Graphical View:

Create an archive file:

tar -zcvf test4. tar. GZ test4/    // Test4 folder as an archive file test4/test4/hh.txttest4/  Yy.txttest4/a.txttest4/lsa.txt  com    file1.txt  httpd.conf  test1  test4. Tar . Gzb.txt  c.txt  file2.doc  test        test4  tests[[email protected] documents]#

Unzip the archive file:

[[Email protected]Tar]#Tar-ZXVF test4.Tar. GZ test4/test4/Hh.txtTar: Test4/hh.txt: TimeStamp -- Geneva- -  .: the: onIs17199.007385938SinchThe futuretest4/Yy.txttest4/a.txtTar: Test4/a.txt: TimeStamp -- Geneva- -  .: the: onIs17199.006267373SinchThe futuretest4/TestTar: test4/test: TimeStamp -- Geneva- -  .: the: onIs17199.005671909SinchThe future[[email protected]Tar]#lstest4 test4.Tar. Gz[[email protected]Tar]#

Linux file archiving and compression (Learn note eight)