Linux file directory compression and decompression command
Compress compression: compress is a compression program with a long history. After a file is compressed, the extension ". Z" will appear after its name.
[root@localhost ~]# yum install -y ncompress
[root@localhost ~]# compress --help
Command syntax:[ compress [option] File or directory ]
-f #Force overwrite target file
-c #Send the result to standard output and no file is changed
-r #Recursive operation mode
-b number #The compression efficiency is between 9 and 16
-d #Decompress the file instead of compressing it
-v #Display instruction execution process
Compress a file by using the compress -c command
[root@localhost ~]# ls -lh total 944K -rwxr-xr-x. 1 root root 942K Sep 26 2017 bash [root@localhost ~]# compress -c bash > bash.Z [root@localhost ~]# ls -lh total 1.6M -rwxr-xr-x. 1 root root 942K Sep 26 2017 bash -rw-r--r--. 1 root root 596K Nov 16 06:38 bash.Z
Extract a file by using the compress -d command
[root@localhost ~]# ls -lh total 596K -rw-r--r--. 1 root root 596K Nov 16 06:38 bash.Z [root@localhost ~]# compress -d bash.Z [root@localhost ~]# ls -lh total 944K -rw-r--r--. 1 root root 942K Nov 16 06:38 bash
Zip compression: the extended name of zip command compression Zip various systems support zip compression format, so it can be used in general to a certain extent
[root@localhost ~]# yum install -y zip unzip
[root@localhost ~]# zip --help
Command syntax:[ zip/unzip [option] File or directory ]
-r #Recursive compression, compressed together with subdirectories
-S #Contains system and hidden files
-v #Display instruction execution process
-q #Instruction execution is not displayed
Compress the entire contents of the / etc / directory by using the zip -r -v command
[root@localhost ~]# zip -r -v lyshark.zip /etc/ [root@localhost ~]# ls -lh total 12M -rw-r--r--. 1 root root 12M Nov 16 09:46 lyshark.zip
Use the unzip -l command to query the files in a compressed package
[root@localhost ~]# unzip -l lyshark.zip
Unzip the file to the specified directory using the unzip -d command
[root@localhost ~]# unzip lyshark.zip -d /tmp/ [root@localhost ~]# ls -lh /tmp/ total 12K drwxr-xr-x. 84 root root 8.0K Nov 6 11:02 etc
Gzip compression: gzip is the default compression format supported by Linux system. It can be used in combination with tar command. Gzip has a compression rate of 60% ~ 70% for text files.
[root@localhost ~]# gzip --help
Command syntax:[ gzip/zcat [option] File or directory ]
-a #Use ASCII text mode
-d #Unpack the compressed file
-f #Force compression of files
-l #Lists information about compressed files
-n #When compressing, the original file name and timestamp are not saved
-N #When compressing, save the original file name and timestamp
-q #Do not display warning messages
-r #Recursive processing
-v #Display instruction execution process
Compress a file by using the gzip -rv command
[root@localhost ~]# ls -lh total 944K -rwxr-xr-x. 1 root root 942K Sep 26 2017 bash [root@localhost ~]# gzip -rv bash bash: 51.2% -- replaced with bash.gz [root@localhost ~]# ls -lh total 460K -rwxr-xr-x. 1 root root 460K Sep 26 2017 bash.gz
Query a file by using the gzip -l/zcat -l command
[root@localhost ~]# gzip -l bash.gz
compressed uncompressed ratio uncompressed_name
470300 964544 51.2% bash
[root@localhost ~]# zcat -l bash.gz
compressed uncompressed ratio uncompressed_name
470300 964544 51.2% bash
Unzip a file by using the gzip -dv / zcat command
[root@localhost ~]# ls -lh total 460K -rwxr-xr-x. 1 root root 460K Sep 26 2017 bash.gz [root@localhost ~]# gzip -dv bash.gz bash.gz: 51.2% -- replaced with bash [root@localhost ~]# zcat -d bash.gz >bash_zcat
Bzip2 compression: the bzip2 command is used for creation and management, including decompression. You must install it before using this command, because this command has no integrated installation
[root@localhost ~]# yum install -y bzip2
[root@localhost ~]# bzip2 --hlep
Command syntax:[ bzip2/bzcat [option] File or directory ]
-c #Output compression decompression process
-d #Perform decompression
-k #Keep the original file after decompression
-v #Detailed output during compression or decompression
-z #Force compression
Compress the bash file by using the bzip2 -kzv command
[root@localhost ~]# ls -lh total 944K -rwxr-xr-x. 1 root root 942K Sep 26 2017 bash [root@localhost ~]# bzip2 -kzv bash bash: 2.164:1, 3.697 bits/byte, 53.79% saved, 964544 in, 445742 out.
Extract bash. Net by using the bzip2 -kdv command Bz2 file
[root@localhost ~]# ls -lh total 436K -rwxr-xr-x. 1 root root 436K Sep 26 2017 bash.bz2 [root@localhost ~]# bzip2 -kdv bash.bz2 bash.bz2: done
tar archive and compress: this command is often used in combination with gz,bz2 and other compression commands.
[root@localhost ~]# tar --hlep
Command syntax:[ tar [option] File or directory ]
-c #New package
-t #View packaged files
-x #Unpack the package file
-j #Compression and decompression through bz2
-z #Compression and decompression through gz
-J #Compression and decompression through xz
-v #Displays the compression and decompression process
-C #Specify where to unzip
Compress, decompress and query by using tar -czvf xzvf tvf command
[root@localhost ~]# tar -czvf lyshark.tar.gz /etc/* #Compress the contents in / etc / * directory into lysark tar. gz [root@localhost ~]# tar -tvf lyshark.tar.gz #Query contents in package [root@localhost ~]# tar -xzvf lyshark.tar.gz -C /etc/ #Unzip the compressed package to the / etc / directory
Compress, decompress and query by using tar -cjvf xjvf tvf command
[root@localhost ~]# tar -cjvf lyshark.tar.bz2 /etc/* #Compress the contents in / etc / * directory into lysark tar. bz2 [root@localhost ~]# tar -tvf lyshark.tar.bz2 #Query contents in package [root@localhost ~]# tar -xjvf lyshark.tar.bz2 -C /etc/ #Unzip the compressed package to the / etc / directory
Compress, decompress and query by using tar -cJvf xJvf tvf command
[root@localhost ~]# tar -cJvf lyshark.tar.xz /etc/* #Compress the contents in / etc / * directory into lysark tar. xz [root@localhost ~]# tar -tvf lyshark.tar.xz #Query contents in package [root@localhost ~]# tar -xJvf lyshark.tar.xz -C /etc/ #Unzip the compressed package to the / etc / directory
cpio block level compression: a tool program used by cpio to create or restore backups. The cpio command can back up anything, including device files.
[root@localhost ~]# cpio --help
Compression syntax:[ cpio –cvBo > [file|equipment] ]
-c #Using portable format storage
-v #Display process
-B #Set the I / O block to 512bytes
-o #Enter copy out mode (compression)
View syntax:[ cpio –ivct < [cpio file] ]
-i #Copy data from file to system
-c #Using portable format storage
-t #View the contents of CPIO compressed package
Restore syntax:[ cpio –idvcu < [cpio file] ]
-i #Enter copy in mode (decompression)
-d #Restore to the specified location (depending on compression)
-v #Display process
-c #Using portable format storage
-u #Replace all files without prompting
Use the cpio -cvBo command to back up the / etc / directory
[root@localhost ~]# find /etc/ -print | cpio -cvBo > /root/etc.cpio [root@localhost ~]# ls -lh total 109M -rw-r--r--. 1 root root 109M Nov 16 10:50 etc.cpio
Use the cpio -cvBo command to back up the contents in the / etc / directory to the / sdb disk
[root@localhost ~]# find /etc/ -print | cpio -cvBo > /dev/vdb
Use the cpio -ivct command to query and compress the package contents
[root@localhost ~]# ls -lh total 109M -rw-r--r--. 1 root root 109M Nov 16 10:50 etc.cpio [root@localhost ~]# cpio -ivct < etc.cpio
Use cpio -idvcu to restore files to the / etc / directory
[root@localhost ~]# ls -lh total 109M -rw-r--r--. 1 root root 109M Nov 16 10:50 etc.cpio [root@localhost ~]# cpio -idvcu < /root/etc.cpio
Create ISO image: the mkisofs command is used to make the specified directory and file into an image file in ISO 9660 format.
[root@localhost ~]# mkisofs --help
Command syntax:[ mkisofs [option] File or directory ]
-o #Followed by image name
-r #Record with file attributes
-v #Show build process
-m #Exclude specified files
-V #New volume
Make an image through mkisofs and make the / etc directory lysark iso.
[root@localhost ~]# mkisofs -r -v -o /root/lyshark.iso /etc/ [root@localhost ~]# ls -lh total 123M -rw-r--r--. 1 root root 123M Nov 16 11:14 lyshark.iso
Disk speed measurement and copy: dd command is used for disk speed measurement and backup. This command is very low-level, so it can complete many functions that cannot be completed by backup tools.
[root@localhost ~]# dd --help
Backup syntax:[ dd [if=source file] [of=output] [count=count] ]
if=file name #Enter file name
of=file name #Output file name
bs=bytes #Read in count
count=blocks #Copy blocks only
/dev/zero #Yes, the device will continue to return 0 value bytes
/dev/null #Empty equipment, equivalent to a trash can
By using dd to measure the disk speed, the disk read-write speed can be measured (1024204840968192 can be tested respectively)
[root@localhost ~]# dd if=/dev/zero of=/dev/null bs=1024 count=10000 10000+0 records in 10000+0 records out 10240000 bytes (10 MB) copied, 0.00852247 s, 1.2 GB/s
Regular disk backup by using dd
#Backup the local / dev/sda disk to / dev/hdd [root@localhost ~]# dd if=/dev/sda /of=/dev/hdd #Backup the full disk data of / dev/sda to the image file of the specified path [root@localhost ~]# dd if=/dev/sda of=/tmp/image #Restore the image backup file to the specified disk / dev/sdb [root@localhost ~]# dd if=/tmp/image of=/dev/sdb #Back up the full disk data of / dev/sda, compress it with gzip tool, and save it to / TMP / image gz [root@localhost ~]# dd if=/dev/sda | gzip > /tmp/image.gz #Restore the compressed backup file / TMP / image GZ, restore to disk / dev/sdb [root@localhost ~]# gizp -dc /tmp/image.gz | dd of=/dev/sdb
Use the dd command to back up the disk MBR and restore the partition MBR
#Back up the MBR. Back up the MBR information of 512 bytes from disk / dev/sda to the specified file / tmp/mbr512 #Where: count=1 refers to copying only one block; bs=512 means that the block size is 512 bytes [root@localhost ~]# dd if=/dev/sda of=/tmp/mbr512 count=1 bs=512 1+0 records in 1+0 records out 512 bytes (512 B) copied, 0.00015245 s, 3.4 MB/s #Restore the MBR and write the MBR information of backup / tmp/mbr512 to the beginning of disk / dev/sda [root@localhost ~]# dd if=/tmp/mbr512 of=/dev/sda 1+0 records in 1+0 records out 512 bytes (512 B) copied, 0.000201242 s, 2.5 MB/s
Copy the memory data and optical disc data to the specified location by using the dd command.
#Copy memory contents to disk [root@localhost ~]# dd if=/dev/mem of=/tmp/mem_ Image BS = 1024 (specify a block size of 1k) dd: error reading '/dev/mem': Bad address 632+0 records in 632+0 records out 647168 bytes (647 kB) copied, 0.001591 s, 407 MB/s #Copy the contents of the disc to the specified folder and save it as / TMP / lysark ISO file [root@localhost ~]# dd if=/dev/sr0 of=/tmp/LyShark.iso 1249+0 records in 1248+0 records out 638976 bytes (639 kB) copied, 0.368021 s, 1.7 MB/s #Fill the disk with random numbers and completely destroy the disk / dev/sdb data [root@localhost ~]# dd if=/dev/urandom of=/dev/sdb