Linux File and directory management

absolute path vs. relative path :

directory and its related operations :

. Represents this Layer directory

.. Represents a previous level directory

-Represents a previous working directory

~ Represents the home folder where the current user identity resides

1.CD Switch Directory

EG:CD.

2.pwd [-p] shows the current directory,-p for not using link path

3.mkdir New Catalog

-M profile permissions----to the cabinet create directory

Eg:mkdir Test

Mkdir-p Test1/test2/test3/test4

Mkdir-m 711 Test2

4.rmdir [-P]

Delete Empty directory,-p means to delete with upper empty directory together

5.rm-r Test

Delete everything under the test directory

$PATH:

file and directory management :

view files and directories ls:

ls [-aadffhilnrrst] directory name

ls [--color={never,auto,always}] Directory name

ls [--full-time] directory name

Parameters:-A All files are listed together with hidden files to

-d lists only the directory itself and does not list the file data in the directory

-l lists Long data strings, including file attributes and permissions, etc.

Eg:ls-al ~ All files under the home folder

PS: Data related to the properties and permissions of the file is placed in the I-node.

copy, delete, and move CP,RM,MV:

CP [-parameter] source destination

-A corresponds to-PDR to copy file attributes together

-I if the target file already exists, please ask before overwriting

-R Recursive Continuous replication

PS: Replication changes file permissions without parameters

RM [-fir] File or directory delete file or directory

-F ignores nonexistent files and does not appear warning

-I interactive mode, ask the user whether to operate before deleting

-R Recursive Delete

MV [-FIU] source destination moving files and directories, or renaming

-f:force mandatory Meaning, if the target already exists, will not ask and will directly overwrite

-I: If the target file already exists, you will be asked whether to overwrite

-U: If the target file already exists and source is newer, it will be updated (update)

EG:CP ~/.BASHRC Bashrc1

CP ~/.BASHRC BASHRC2

MV Bashrc1 Bashrc2 Mvtest2

get path filename and directory name :

Eg:basename/etc/sysconfig/network

Dirname/etc/sysconfig/network

file content Check :

A. Directly viewing the contents of a file, you can use cat/tac/nl several commands

Cat [-abentv]

-N Prints the travel number, along with a blank line, which also appears.

-B blank line does not print line number

Eg:cat-n/etc/issue

TAC /etc/issue

Reverse Display

NL [-BNW] File

Add line numbers to print

B. Can flip view

More/etc/man.config one page, one page flip

less/etc/man.config One-page flip, including pages that can be used with [page UP]

C. Data read

Head out the first few lines

tail [-N number] file take the following lines

Non-plain text file: OD

Modify file time or create a new file: Touch

Modification Time (mtime):
This time will be updated when the content data of the file is changed!
Status Time (CTime):
When the status of the file changes, it is updated

Access Time (Atime):

Update Atime Read time when file contents are fetched.

File default permissions: unmask

Preset permissions: File 666 directory 777

File Hidden properties:

Chattr setting file-hidden properties

Lsattr Show file Hidden properties

File Special permissions: Suid,sgid,sbit

When Suid:s appears on the file owner's permission x, it becomes SUID, such as-rwsr-xr-x, whose function is

Suid only valid for binary programs

Performer must have X Execute permission on the program

This permission is valid only during the execution of the program

Performer will have change owner permissions

Sgid:s on X of user group

Sgid can be set for files or directories, not only useful for binary programs

Program performer has x permission on the program

The performer needs to be supported by the program user group during the execution.

Sbit: only valid for directory

When a user has w,x permissions on this directory, when Write permission is available:

When a user creates a directory file under this directory, only himself and Root have the right to delete the file

Large s,t, with special permissions set but no x permission

Viewing file types: File files

Command and file query: which looking for "execute file"

which the executable file according to the directory within the path variable set by the user

/sbin is not in Vbird's path.

and cannot find the bash built-in commands

File name lookup: Whereis

Locate

Whereis Locate is a database lookup

UpdateDB: Updating database files

Find

The relationship between permissions and commands: