Quick Query manual for common Linux commands (IV)

A. add A file to an existing backup file.-c: create A backup file.-d: compare the differences between the backup file and the files in the current directory. when-k unlocks the backup file,

Other common tools

1.bzip2

Note: bzip2is the compression tool for .bz2 files.

Syntax: bzip2 [-cdfkqstvVL] [-1 |-2 |-3 |-4 |-5 |-6 |-7 |-8 |-9] [filename]

Parameter:-c: compress/decompress the file to the standard output device;-d: decompress;-f: if the existing file and the decompressed output file are duplicated, overwrite the existing file; -k retains the input file (the source file) after decompression;-q disables unnecessary warning information;-s reduces the memory required for running the command;-t checks the integrity of the file; -v: displays details when working.-V: displays version information.-L: displays License information.-1 ~ -9 set the compressed block size, that is, kB ~ The compression process is 900 KB.

2. cal

Description: displays a simple calendar.

Syntax: cal [-mjy] [[mouth] year]

Parameter:-m indicates that Monday is the first day of a week. The default value is Sunday.-j is displayed in Julina format, that is, every month; -y: displays the calendar of all months of the current year.

3. cdplay

Description: a playback tool in Linux.

Syntax: cdplay [-c device] [-lns] [play] [stop] [table]

Parameter:-c device specifies the playing device;-l waits for peripheral device initialization;-n disables automatic playback;-s disables audio mode; play automatically plays CD from num track; stop to stop playing CD. table displays CD content from the database.

4. compress

Note: compress is A. Z file compression/decompression tool.

Syntax: compress [-cdfrvV] [-B <压缩效率> ] [File or directory…]

Parameter:-c outputs the compressed file to the standard output device without modifying the original file. By default, the compress command will compress the file directly and add. Z extension. the original file is not retained;-d is used to decompress the file;-f is used to forcibly save the compressed file;-r is used to recursively process all files and subdirectories in the specified directory; -v indicates the instruction execution process.-V indicates the instruction version and program preset value.-B <压缩效率> 9 ~ The default value is 16. the larger the number, the smaller the size of the compressed file, and the more time it takes.

5. grep

Description: searches for matching strings in the file.

Syntax: grep [-qrv] [style] [File/directory name…]

Parameter:-q does not display any information about the intermediate process. if-r uses this option, it searches for the content of all files and subdirectories in the specified directory, that is, to find columns that do not contain strings specified by "style.

6. gzip

Note: To compress/decompress the compressed file, the generated compressed file is suffixed with ". gz ".

Syntax: gzip [-dfl] [- <压缩效率> ] [File…]

Gzip [-dflr] [- <压缩效率> ] [Directory]

Parameter description:-d extract;-f forcibly compress the file and directly overwrite the file with the same name;-l lists information about the compressed file, including the size, compression ratio, and file name before and after compression; -r: compress all files and subdirectories in the specified directory to this file ;- <压缩效率 > Is a 1 ~ The smaller the number, the faster the compression, the larger the number and the higher the compression ratio.

7. tar

Note: it is the most commonly used tool for establishing and restoring backup files in Linux/Unix systems.

Syntax: tar [-Acdkvx] [-f <备份文件> ] [File/directory…]

Parameter:-A adds A file to an existing backup file;-c creates A backup file;-d compares the differences between the backup file and the files in the current directory; -k does not overwrite existing files when unmounting the backup file;-v displays the command execution process;-x restores the contents of the backup file;-f <备份文件> Specifies the backup file name.