Python Learning record--ubuntu (iii) file operations

A. mkdir is used to create a directory:

mkdir Directory name #创建目录

Mkdir-p Directory name 1/directory Name 2/directory name 3 #创建多层目录

Two. RM for deleting files ( Use caution, easy to trigger program crashes ):

1. Parameters

(1) RM file name #只能删除文件, but cannot delete directory

(2) rm-i file name #会出现提示

(3) rm-f file name #强制删除

(4) RM-RF directory name #强制删除目录

Three. MV is used to move or rename files/directories:

1. Example

(1) MV File/directory name new File/directory name #重命名文件/directory

(2) MV FileName Directory name #将文件移至目录下

(3) MV File/directory name. #移动至当前目录

Four. CP for copying Files:

1. Example

(1) CP filename New file name #在当前目录复制文件并重新命名

(2) CP directory name/new directory name # Note Directory replication to add/

(3) CP -a filename new file name #复制文件, and retain the original permission and owner

five .> for redirection (write file):

(1) > redirect, if the file exists, then overwrite the file content, file does not exist when creating the file

(2) >> Redirect, if the file exists, append the content to the file, and the file does not exist when the file is created

(3) 1> standard correct output, same as cover

(4) 1>> standard correct output, same as Append

(5) 2> standard error output, same as overlay

(6) 2>> standard error output, same as Append

(7) &> standard correct output and standard error output, same as overlay

Eg:cat 123.txt 1>a 2>b #如果正确输出则a有内容b没有

Vi. File Attributes modification:

1.chmod for modifying file permissions

(1) chmod u (on behalf of user users)/g (on behalf of group user groups)/O (on behalf of others others)/A (for all) =rwx (permissions for Read and write execution, no permissions used-instead)./File name #修改文件权限

(2) chmod u (on behalf of user users)/g (on behalf of group user groups)/O (on behalf of others others)/A (on behalf of all) +/-rwx (permissions for Read and write execution, no permissions are not written)./file name #可用加/minus way to modify permissions

(3) chmod corresponds to three digits./File name #修改文件权限

(4) can also use the number to represent the authority: R:4,w:2,x:1 Rwx:7,rw:6,rx:5

2.chown for modifying file owners and all groups

(1) Chown name file name #更改所有者

(2) Chown: name filename #更改所有组

(3) Chown name: Name File name #更改所有者和所有组

Seven. LS is used to view file information:

1. Parameters

(1) LS #查看当前目录下可见的文件

(2) Ls-a #查看当前目录下所有文件, if the document is in front of the hidden file; Represents the current directory and parent directory, respectively

(3) Ls-l #显示所有文件及详细信息

(4) ls-l./File name #显示该文件详细信息

The details are displayed in the following format:

File types (-for normal files, d for catalog files, b for block device files, c for character device files, L for link files (e.g. shortcuts), p for pipe files, s for socket files)

For example:-rwxrwxrwx,-is the file type, R is readable (whether the directory can read the file name in the folder), W is writable (whether the directory can create and modify files in the directory), X is executable (whether the directory can be searched/able to enter the directory)

3 groups, which represent the user, user group, other people's file operation permissions

　　　　in ./When executing a file, the user must have X permission on the file

Digital

Owner

User groups belonging to

File size (default is bytes, LS-LH can be changed to KB, directory default is 4096 bytes)

Date Modified

Filename

(4) Ls-lt #附加以时间排降序 (if R is added after T, can be changed to ascending)

(5) Ls-r #遍历所有文件目录

Eight. Common file Operation command:

1. Change the current directory

(1) cd+ address #更改目录至制定地址, such as Cd/home; CD ~/Desktop

(2)CD. #返回当前目录的上一级目录

(3) cd-#返回到当前目录之前打开的目录

(4) CD #回用户家目录

2.touch file name #将文件时间修改成当前时间, such as the time to consolidate multiple files

3.cat file name #查看文件内容

Cat-s the file name #将多个空行合并成一个空行, but the row is not merged if there are spaces within it

4.TAC file name #从下往上输出文件内容

5.sort #排序

(1) Sort-r #反向排序

(2) Sort-n #使用纯数字排序

(3) Sort-f #忽略大小写

(4) Sort-t separator #指定分隔符

6.uniq #忽略或报告重复行

Uniq-c #进行计数

Uniq-u #不显示重复行

Uniq-i #不区分大小写

7.cut #提取文本列

Cut-d delimiter-F column number

Cut-c #以字符为单位提取 such as: cut-c 1,5 extract first and fifth words, Cut-c 1-5 extract first to fifth words

8.tee #读取标准输入的数据 and output its contents as a file

9.history #列出历史命令

History number #显示最近多少条命令

History!number #执行第几条命令

10.more/less file name #分页显示, space to display the next page, enter to display the next line, B fallback, q exit

11head/tail file name #显示前/After 10 lines of text

　　Tail-f file name #实时监控文件变化, can be used on log file monitoring

12.which Command #查命令在什么位置

13.stat file name #用于查看文件信息:

14.pwd #查看当前目录

1. Alias #用于给命令起别名

Alias alias = ' formerly ' #如: Alias la= ' Ls-a '

If an alias is required to be permanent, it needs to be saved to the. bashrc file

16.source file name #在当前bash环境下读取并执行FileName中的命令, the filename file can have no "execute permission"

17.echo #可用于在屏幕上打印文件内容, echo-n non-newline output

18.df-th #以能显示的最大单位显示文件系统类型

18.du-s (if the directory is followed, only one layer is displayed)-H (displayed in the largest units that can be displayed) directory name #显示目录的大小

Nine. File Search:

1.locate:

(1) LOCATE/ETC/SH # Search path contains/etc/sh files.

(2) Locate ~/a # Search the user home directory, all files beginning with a.

(3) Locate-i #忽略大小写.

　　Locate you find a file, you cannot find the file if the database is not updated in a timely manner, you can update the database manually by using the sudo updatedb command

2.find:

(1) How to use: Find Path-option [-print] [-exec-ok command] {} \;

(2) Search by file name:

Find directory-name file name #在目录里面搜索某文件名的文件

Find/home-name "*.txt" #在家目录里搜索txt后缀的文件

Find/home-iname "*.txt" #忽略大小写

(3) Search by file type:

Find directory-type type parameter f normal file L symbol connection D directory C character device B block device s socket p FIFO

(4) Search by directory depth:

Find. -maxdepth 3-type F # Find from current directory, max depth is 3

Find. -mindepth 2-type F # Minimum depth of 2

(5) Search according to the file's permission or size name type:

Find directory-type f-size (+|-) file size # + = Greater than-Indicates less than

b--block (512 bytes) c--byte w--Word (2 bytes) k--Kbytes m--megabytes g--gigabytes

(6) Search by Time:

-atime (+|-) n # This option represents finding files that were read n days ago.

-mtime (+|-) n # This option represents a file that finds the content of a file that was changed n days ago.

-ctime (+|-) n # This option represents a file that looks for changes to the properties of files that were older than n days.

-newer File # This option represents finding out all the new files that are newer than document.

-newer file1! –newer File2 # This option represents a new file that looks for newer files than the File1 file time but does not have file2 time.

Attention:

N is a number, and if there is no + or-number, it represents a file that has been changed in the range of a day, but only for a period of the past n days.

If n is preceded by A + sign, it represents a file that has changed before n days. If it is a minus sign, it means finding all files that have changed within the N-day range.

-newer file1! –newer File2! is a logical non-operator

(7) Search by user/authority:

-user user name: Finds files based on the file's owner name.

-group group name: Finds files based on the file's group name.

-uid N: Finds files based on the UID of the file owner.

-gid N: Finds files according to the GID of the file group.

-nouser: The query file belongs to a file that does not exist in the/etc/passwd file.

-nogroup: Querying files belonging to a file that does not exist in the/etc/group file

-perm 777: Query permissions of 777 files

(8) Specify multiple criteria when searching:

-O: Logical OR, two conditions as long as one is satisfied.

-A: Logic with, two conditions must be met at the same time.

Find/etc-size +2m-a-size-10m

(9) Processing the results of the search:

-exec shell command {} \;

-ok shell command {} \; Recommended

Where the-exec is to execute the shell command, followed by the shell directive, and then the "{}" is to query the results of the previous query, the last "\;" indicates the end of the command. It is important to note that the " {} "and" \ "There is a space between." The only difference between the-OK option and-exec is that it asks for it in advance of executing the shell command.

The-print option is to display the results on standard input

10. Program Writing terminal gedit:

Write #! at the beginning of the file /usr/bin/env Python3 #用于指定解释器为python3, which specifies that files can be executed in./File name mode later

Python Learning record--ubuntu (iii) file operations