Linux Learning 3

For several days did not summarize on the net. I copied the PPT first in the book, so that when the record is convenient to listen to a lot of things, add something to it.

I want to look at the shell first, but without the preparation of the previous chapters, I can't do it with the video. So it's a step-by-step study.

Although the book in detail, but find out, online more convenient.

Iv. Common commands for documents

4.2 Rights Management Commands

4.3 File Search command

4.4 Help Commands

4.5 User Management commands

4.6 Compression Decompression Command

4.7 Network Commands

4.8 Power off Restart command

4.2 Rights Management

--chmod only root and file owners can change permissions

-R Recursive modification

R-4, W-2,x-1. Permissions on the directory, r, can enter, X, can list the contents of the directory, RX must exist at the same time. W, create/delete files in directory

eg, chmod g+w testfile, Chmod-r 777 TestDir

___chown only the root user can modify

Eg,chown UserA filename

___chgrp

___umask the user file-creation mask

-S: Displays the new file default permissions as RWX, otherwise in the form of data, such as 0022

0022: The first 0 represents a special permission. The remaining 022, with 777-022 being the true permission value

Default file permissions do not have x Execute permission, for security, antivirus so that it cannot run

When modifying permissions, the values to be modified, such as Rwxrwxr-x 775, need to be written to 777-775=002, eg, umask 0002

____ File Search command

__find

find[search scope [search criteria]

__find/etc-name init *init* Init???

-iname Case insensitive

__find/-size +204800//Find files larger than 100MB

+n is greater than, n is less than, N equals.

A data block is 512 bytes, 0.5k. 100M = 102400kb, * * = 204800 data block

So if 1m,1024*2= 2048

__find/home-user Sophie

-group

__find/etc-cmin-5//Find files and directories with modified properties in 5min

-amin Accessing Time Access

-cmin File Properties Change ... This is a little hard to remember, analogy chmode.

-mmin File Contents Modify

__find/etc-size +163840-a-size-204800//163840/2=81920/1024=80m

-a two conditions satisfy and

-O satisfies an OR

__find/etc-name inittab-exec ls-l {}\;

-exec/-ok command {}\; where {} represents the find result, \ is an escape character;

The result of-ok is that there will be an inquiry

__-type f,d,l

__inum based on I-node lookup

The _____locate is found in the file repository. Can save system and CPU resources, faster

Files in the system are periodically saved to the file repository. The/tmp folder will not be saved to the file repository.

-updatedb can update the file repository immediately

___which the directory where the search command resides and its alias information

The directory where the ___whereis command resides and its help document path

___grep

grep-iv[the specified string [file]//search for a string-matched line in the file and output

-I is case insensitive

-V excludes the specified string

eg, #grep Mysql/root/install.log

4.4 Help Commands

___man Manual

/content, can be searched, press N, check next

Commands: View name, description, Options

Configuration: View name, file format

Eg,man ls

eg, man Services//profile name, no path

Search for a short message instead of man:

__whatis + command, view name, description

__ Commands +--HELP, see options

__appropos + configuration, view name

___help

Help Umask

View Help for Shell built-in commands

　　

　　

　　

Linux Learning 3