0801linux Basic Content Small note

Cat > F1 << EOF Multi-line submission

Mail-s Test user1 << End

> Nice to meet u

> Let ' s Go

> End

ll/etc/| Less paging display

ls/tmp | Tee/tmp/a.log

Tee Command Save information,-a append

TR [[: Lower:]] [[: Upper:]] < F1 convert standard input of F1

Xecho ASDFG |& tr ' A-Z ' A-Z ' equivalent notation:

Xecho ASDFG 2>&1 | tr ' A-Z ' A-Z '//

TR [option] Set1 Set2

-c,--complement: Complementary set

-D: Delete all characters belonging to the first character set

-T: Remove characters from the first character set that are more than the second character set

-s,--squeeze-repeats: Repeats consecutive characters in a single character

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M01/85/4C/wKiom1efUBqwjAHIAAHhf0jaPnA484.png "title=" TR option. png "width=" "height=" 722 "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:700px;height:722px; "alt=" Wkiom1efubqwjahiaahhf0japna484.png "/>

Getent passwd user1

Getent Shadow User1

Getent Group User1

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M00/85/4C/wKioL1efUO3Ros0OAACauA6PfJk332.png "title=" Getent.png "width=" "height=" 127 "border=" 0 "hspace=" 0 "vspace=" 0 "style=" WIDTH:700PX;HEIGHT:127PX; "alt=" Wkiol1efuo3ros0oaacaua6pfjk332.png "/>

Useradd Tom in the/home/to generate the Tom directory, belong to the main group of Tom

Userdel Tom/home/tomcat, the genus of the main genera, the ID number

Useradd Alice/home/tomcat of the genus Alice

pwunconv: PAWWD Unconvert does not convert,/etc/shadow file is not, before the shadow file stored encrypted password displayed in the second bit of/etc/passwd

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M00/85/4C/wKioL1efUsvyIl30AABYYg_Ew_o592.png "title=" Pwunconv.png "width=" "height=" "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:700px;height:55px; "alt=" Wkiol1efusvyil30aabyyg_ew_o592.png "/>

pwconv: Shadow File Recovery

ID 0 is the administrator, if the/etc/passwd root and other users such as User1 UID swapped, then user1 as the administrator, root for the ordinary user

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M02/85/4C/wKioL1efVDaQIJLNAAA1c0sAVpo822.png "title=" id=0. PNG "width=" height= "border=" 0 "hspace=" 0 "vspace=" 0 "style=" WIDTH:700PX;HEIGHT:57PX; "alt=" Wkiol1efvdaqijlnaaa1c0savpo822.png "/>

CHFN User1 Modify Name,phone,office,shell information

Finger Command View

650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M02/85/4C/wKiom1efVNewRxdGAABtGvRnka8257.png "title=" Finger.png "width=" "height=" 169 "border=" 0 "hspace=" 0 "vspace=" 0 "style=" WIDTH:700PX;HEIGHT:169PX; "alt=" Wkiom1efvnewrxdgaabtgvrnka8257.png "/>

Getent passwd user1 display

user1:x:1001:1001: User 1,magedu,010,12315:/home/user1:/sbin/nologin

Chsh-s/sbin/nologin User1

Change the shell of User1, this user cannot log in

Usermod-l Alice//Lock Login

Usermod-u Alice//Unlock login, will remove an exclamation mark

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M01/85/4F/wKioL1ef9qzyYZ1-AADPNb6jjvA552.png "title=" Lu parameter. png "Width=" "height=" 158 "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:700px;height:158px; "alt=" Wkiol1ef9qzyyz1-aadpnb6jjva552.png "/>

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M01/85/50/wKioL1ef--XyeJySAACQgEcVdTM401.png "title="-u.png "Width=" "height=" 151 "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:700px;height:151px; "alt=" Wkiol1ef--xyejysaacqgecvdtm401.png "/>

Authconfig--passalgo=sha256--update//Update encryption algorithm

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M01/85/50/wKioL1egAtfStsQJAAF8qLCNDSk369.png "title=" Authconfig.png "width=" "height=" 385 "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:700px;height:385px; "alt=" Wkiol1egatfstsqjaaf8qlcndsk369.png "/>

OpenSSL rand-base64 10//

/etc/passwd each meaning- user name: password: User identification number: Group ID: annotative Description: Home directory: Login Shell

echo $[' date +%s '/86400]//output 17014,unix number of days to today

Windows cmd> Net accounts see the password for a maximum age of 42 days

Passwd-e Alice//Alice user login prompts for password change

/etc/group user1:x:1001: After adding Alice, add Alice to the User1 group

ID Alice or groups Alice to see the group information that Alice belongs to

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M00/85/51/wKiom1egCFOwtKl4AABD0UfRBfM147.png "title=" Idgroups.png "width=" "height=" "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:700px;height:125px; "alt=" Wkiom1egcfowtkl4aabd0ufrbfm147.png "/>

Usermod-ag User2 Alice//Add Alice to the User2 group

alice# newgrp user2//Temporary switch main group, exit exit

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M02/85/52/wKiom1egDuSDwdQdAADdiYUoPAQ429.png "title=" Newgrp.png "width=" "height=" 281 "border=" 0 "hspace=" 0 "vspace=" 0 "style=" width:700px;height:281px; "alt=" Wkiom1egdusdwdqdaaddiyuopaq429.png "/>

VIPW command to modify/ETC/PASSWD content

VIGR command to modify/etc/group content

PWCK command Check password file

GRPCK command Inspection of the file

Useradd-u 0-o Rooter

useradd-d/testdir/user4 user4//Automatically create home directory useradd-d//display default user information, can be modified in/etc/default/useradd

The. bash_profile files in the home directory are all originated from the/etc/skel

/etc/login.defs can change the password expiration time, length and other properties

Usermod-u 20010-g user1-g bin,root-s/bin/csh-d/testdir/hehedir-m-C "hehe test"-l NEWHEHE-E 2017-08-01-f Ten heh E

-M: Migrating home Directory-L: New name-e: Specify user account expiration date-F: Expiration How many days are locked

Groupmems-l-G root//view the user of the root group groupmems-d alice-g bin//Remove the Alice user from the bin group groupmems-a alice-g root//Will Alice Add to root group groupmems-p-G bin//To empty the bin group user,-p,--purge

Groups Newhehe//See which groups Newhehe users belong to

Usermod-g "" Alice//Remove Alice's secondary group

strace command to view system calls

SU-XXX login switch, will read the target user's profile, switch to home directory, completely switch

Su XXX non-logon switch, that is, does not read the target user's profile, does not change the current working directory

Su [-] username-c ' COMMAND '

Su-root-c ' Cat/etc/shadow '//switch to root, execute command, and then exit--Triad

0801linux Basic Content Small note