File system access list (FACL) and user and Linux endpoints

Facl:filesystem Access Control List

Save additional access control permissions with file extensions

Tom

Tom,tom Basic Group

jerry:other:r--

Chown: Only Administrators have permission

jerry:rw-

Setfacl

-M: Set, attach

U:uid:perm (permissions)

G:gid:perm

-X: Cancel

U:uid

G:gid

Getfacl

Several commands:

W

W.H.O.

Exercise: Check to see if Hadoop is logged in every 5 seconds, such as logging in, showing that it is logged in, and launching

Sleep

WhoAmI

Last xianshi/var/log/wtmp file, showing user login history and System restart history

-N #: Displays information about recent # times

Lastb,/var/log/btmp file that displays user error login attempts

-N #:

Lastlog: The last logon time per user of the current system

-u username: Displays the most recent login information for the specified user

BaseName

$: Script path and name when executing script

Mail

Hostname: Displays host name or Echo $HOSTNAME

If the host name of the current host is empty, or (none), or localhost, change it to www.baidu.com

[-Z ' hostname '] | | [' hostname ' = = ' (none) '-o ' hostname ' = = ' localhost '] && hostname www.baidu.com

Generate random numbers

random:0-32768 Echo $RANDOM

Write a script that uses random to generate 10 random numbers and find out its maximum, and minimum value

#!/bin/bash

#

Declare-i max=0

Declare-i min=0

For I in {1..10}; Do

Myrandom= $RANDOM

[$I-eq 1] && min= $MYRANDOM

If [$I-le 9]; Then

Echo-n "$MYRANDOM,"

Else

echo "$MYRANDOM"

Fi

[$MYRANDOM-gt $MAX] && max= $MYRANDOM

[$MYRANDOM-lt $MIN] && min= $MYRANDOM

Done

Echo $MAX

Echo $MIN

Random number generator:

/dev/random

/dev/urandom

Terminal type

Console: Consoles

Pty: Physical Terminal

TTY: Virtual Console

TTYs: Serial Terminal

pts/#: Pseudo Terminal

This article is from "Wilson's IT Career" blog, be sure to keep this source http://wilson20.blog.51cto.com/8385324/1426628