Shulou(Shulou.com)06/02 Report--

File lookup

File lookup: locate, find

   non-real-time lookup (database lookup): locate

   real-time search: find

Locate

Common option

-I case-insensitive search 

-n N enumerates only the first N matching items 

-r uses basic regular expressions

Example

Trigger the establishment of a file index database

Find a file

Locate-I-n: find the first three lines of the passwd file

Locate-r: search for files ending in passed

Find

Real-time search tool to complete file search by traversing the specified path

Find [OPTION]... [search path] [search condition] [processing action]

   lookup path: specify a specific destination path; default is the current directory

   search criteria: specified search criteria, such as file name, size, type, permissions, etc. Default is to find all files under the specified path.

   processing action: operate on files that meet the criteria, and output to the screen by default

Search condition 1. Look up by file name and inode:

-name "file name":   supports using glob

*,?, [], [^]-iname "File name":   is not case-sensitive

-inum n   search by inode number

-samefile name   files with the same inode number

-links n files with n   links

-regex "PATTERN":   matches the entire file path with PATTERN, not the file name

Example

The first level directory under root

Between the first and second levels

Find-depth: displays the file first, and then the parent directory

Find-name: find by file name

Find-iname: look up based on file name, case-insensitive

Find-inum n: find by inode node number

Find-samefile name: files with the same node node number

Find-links n: the condition that the number of links is n

Find-regex: matches the entire file path

two。 Look up according to the owner and group:

-user USERNAME: find files whose owner is the specified user (UID)

-group GRPNAME: find files that belong to the specified group (GID)

-uid UserID: find the file whose owner is the specified UID number

-gid GroupID: find files with the specified GID number in the group

-nouser: find files without owners

-nogroup: find files that do not belong to a group

Example

Find-user: find the owner wang

Find-nouser: find files without owners

3. According to the file type

-type TYPE

F: ordinary files

D: catalog file

L: symbolic link file

S: socket file

B: block device file

C: character device file

P: pipe file 

Empty file or directory

  -empty

    example: find / app-type d-empty

Example

Find-type d: list only the directories under home

Find-empty: find the list of empty directories under home

4. According to the combination condition

Combination conditions:

And:-a

Or:-o

Non:-not! 

De Morgan's law:

   (not A) or (not B) = not (An and B)

   (not A) and (not B) = not (An or B) 

Example:

  ! a-a! B =! (a-o B)

  ! a-o! B =! (A-a B)

Example

Find-name snow.png 

Find-iname snow.png 

Find /-name "* .txt" 

Find / var-name "log" 

Find-user joe-group joe 

Find-user joe-not-group joe 

Find-user joe-o-user jane 

Find-not (- user joe-o-user jane) 

Find /-user joe-o-uid 500

Find the files in the / tmp directory where the owner is not root and the file name does not start with f

   find / tmp (- not-user root-a-not-name'f')-ls

   find / tmp-not (- user root-o-name'f')-ls 

Exclude directory 

Example:

Look for all files with the .conf suffix under / etc/ except the / etc/sane.d directory

   find / etc-path'/ etc/sane.d'-a-prune-o-name "* .conf"

Find all files with the .conf suffix under / etc/ except / etc/sane.d and / etc/fonts

   find / etc (- path "/ etc/sane.d"-o-path "/ etc/fonts")-a-prune-o name "* .conf"

Find-a: find an empty directory list under home and the name contains mage characters

Find-o: find an empty list of directories under home or names that contain mage characters

Find-not /!: find the list of non-directories under home

5. Based on file size

-size [+ | -] # UNIT

Common units of   : K, M, Gregory c (byte)

# UNIT: #-1, #]

   such as: 6k means (5kBI 6k)

-# UNIT: [0memorie muri 1]

   such as:-6k means [0pje 5k]

+ # UNIT: (# ∞)

   for example: + 6k means (6k, ∞)

Example: find-size:

6. According to the timestamp

In terms of "days"

  -atime [+ | -] #

     #: [#, # + 1)

     + #: [# + 1, ∞]

    -#: [0Jing #)

  -mtime

  -ctime

In "minutes"

  -amin

  -mmin

  -cmin

Example: find the files that appear within one minute

7. Find based on permissions

-perm [/ | -] MODE

   MODE: exact permission matching

   / MODE: as long as one of the permissions of any kind of object can be matched, or relationship, + be eliminated from centos7

  -MODE: each type of object must also have the specified permissions, and the relationship

   0 indicates no concern.

Find-perm 755 will match files whose permission mode happens to be 755

Find-perm + 222will match as long as anyone has write permission

Find-perm-222will match only if everyone has write permission.

Find-perm-002will match only if someone else (other) has write permission.

Example

Find files with permissions of 600

As long as one of the main subordinate groups has r permission

All subordinate groups must have r permission.

Processing action

Example

-ls: execute the ls-l command on the found file

-delete: delete if you find it

-fls: all files under data found are saved to the specified file.

-ok: the user is asked to confirm when executing the command

-exec: execute the command directly without confirming the user

Parameter replacement because many commands do not support pipes | to pass parameters, xargs is used to generate parameters for a command, xargs can read data from stdin and separate stdin data into parameters with spaces or carriage returns. Many commands cannot accept too many parameters, and command execution may fail. Xargs can solve  Note: file names or nouns with other meanings contain spaces. Combination of  find and xargs: find | xargs COMMAND example

Ls | xargs rm deletes a large number of files in the current directory

Find / sbin/-perm + 700 | ls-l this command is incorrect

Find / bin/-perm / 7000 | xargs ls-Sl looks for files with special permissions and sorts them

Find / bin/-perm-7000 | xargs ls-Sl what is the difference between this command and the above command?

Find-type f-name "* .txt"-print0 | xargs-0 rm is separated by the character nul

Delete all files that begin with l

Build ten users at a time

Separated by the character 0

Find example

Back up the configuration file and add the .orig extension

Find-name "* .conf"-exec cp {} {} orig\; 

Prompt to delete temporary files of joe that have existed for more than 3 days

Find / tmp-ctime + 3-user joe-ok rm {}\; 

Look for files in the home directory that can be written by other users

Find ~-perm-002-exec chmod Omurw {}\; 

Find ordinary files with the permission of 644 and suffix sh under / data, and increase the execution permission

Find / data-type f-perm 644-name "* .sh"-exec chmod 755 {}\; 

View the directory of / home

Find / home-type d-ls

Compression, decompression and archiving tool compress/uncompress-d decompression, equivalent to uncompress

-c output the result to standard output without deleting the original file

-v display details uncompress file.Z decompress  zcat file.Z to view the contents of the text file without explicit decompression

Example: zcat file.Z > file example

Compress: compressing m.txt files

Compress-d: decompress

Caompress-c: compress and retain the original file

Zcat: view the contents of unextracted files

Gzip/gunzip-d decompression, which is equivalent to gunzip

-c output the result to standard output, leaving the original file unchanged

-# specify compression ratio. The value of # is 1-9. The greater the value, the greater the compression ratio. Gunzip file.gz decompress  zcat file.gz without explicit decompression to view the text file content .

Example: gzip-c messages > messages.gz gzip-c-d messages.gz > messages zcat messages.gz > messages cat messages | gzip > m.gz example

Gzip: compressing files

Gzip-9: the higher the value, the greater the degree of compression.

Gzip-d: extract files

Gunzip m.txt.gz: extracting files

Bzip2/bunzip2/bzcat-k keep, keep the original file

-d decompression

-# 1-9, compression ratio. Default is 9bunzip2 file.bz2 decompression  bzcat file.bz2 without explicit decompression to view the text file content example

Bzip2: compressing files

Bzip2-k: compress and retain the original file

Bzip2-d: decompress

Bzcat: view the contents of unextracted files

Xz/unxz/xzcat-k keep, keep the original file

-d decompression

-# Compression ratio. Value is 1-9. Default is 6  unxz file.xz decompression  xzcat file.xz without explicit decompression to view text file content examples.

Xz: compressing files

Unxz m.xa: decompression

Zip/unzip Packaging Compression

   zip-r / backup/sysconfig / etc/sysconfig/  unpacking and decompression

   unzip sysconfig.zip

   cat / var/log/messages | zip messages-

   unzip-p message.gz > message-p means pipe

Zip: package compression

Unzip: unpack

Tar (1) creates an archive with reserved permissions

   tar-cpvf / PATH/FILE.tar FILE...

(2) append files to archives: note: appends to compressed files are not supported.

   tar-r-f / PATH/FILE.tar FILE...

(3) View the list of files in the archive file

   tar-t-f / PATH/FILE.tar

(4) start filing

   tar-x-f / PATH/FILE.tar

   tar-x-f / PATH/FILE.tar-C / PATH/

(5) implement with compression tools: archive and compress   -j: bzip2,-z: gzip,-J: xz--exclude excluded files

   tar zcvf / root/a3.tgz-- exclude=/app/host1-- exclude=/app/host2 / app -T option specifies the input file-X option specifies the list of files to exclude

   tar zcvf mybackup.tgz-T / root/includefilelist-X / root/excludefilelist  split: split a file into multiple files

   splits large tar files into multiple small files

   split-b Size-d tar-file-name prefix-name

   split-b 1m-d mybackup.tgz mybackup-parts

   split-b 1m mybackup.tgz mybackup-parts

   merge:

   cat mybackup-parts* > mybackup.tar.gz example

Tar cvf: package / var/log named log.tar

Tar tf: preview file list

Tar xvf: unpack any compression:

Unzip to the / tmp directory

Tar zcvf: packaged and compressed

Cpio function: package file or unpack  cpio command is a tool to package and restore files through redirection. It can extract files ending in ".cpio" or ".tar"  cpio [option] > file name or device name  cpio [option]

< 文件名或者设备名 选项  -o  output模式，打包，将标准输入传入的文件名打包后发送到标准输出  -i   input模式，解包，对标准输入传入的打包文件名解包到当前目录  -t  预览，查看标准输入传入的打包文件中包含的文件列表   -O filename 输出到指定的归档文件名  -A  向已存在的归档文件中追加文件  -I filename  对指定的归档文件名解压  -F filename  使用指定的文件名替代标准输入或输出  -d   解包生成目录，在cpio还原时，自动的建立目录  -v  显示打包过程中的文件名称示例 将etc目录备份：   find ./etc -print |cpio -ov >

Bak.cpio 

Append / data content to bak.cpio

   find / data | cpio-oA-F bak.cpio 

Content preview

   cpio-tv < etc.cpio 

Unpack a file

   cpio-idv < etc.cpio

Preview the list of files in the packaged file

Unpack the generation directory

Practice

Count the number of lines of all .c suffix files in the operating system

Count the number of lines of code in c language in the operating system

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