2016-5-15 Linux Basic Learning--case statement

File system access list
Facl: Saving control permissions with file extensions
Permission Application order: Ower->group->other
Ower->facl in User->group->facl in Group->other
Setfacl
-M: Set
U:uid:perm Setting Owner
G:gid:perm set Genus
Eg:setfacl-m U:HADOOP:RW Set Read and Write permissions to Hadoop users
-X: Cancel
U:uid:perm Cancellation of Owner
G:gid:perm cancellation of genus Group
Getfacl:
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W.H.O.: Shows which users are currently logged on
Who-h: Display Head
Sleep
Every 5 seconds, check to see if Hadoop is logged in, sign in, show that it is logged in, and exit
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WhoAmI: Displays the currently logged on user     
last : Display /var/log/wtmp file showing user login history and System restart history
    -n #: Show information about recent # times
lastb: /var/log/wtmp file, Display user error logon attempts
Lastlog: Displays information about the most recent successful login for each user
    -u USERNAME: Displays recent login information for a specific user

basename : Take a file/path base name (file name itself)
    $0: Script path and name when executing script
    
    eg: Cat/etc/fstab | Mail-s "How is it?" Root
     Second, mail "Recipient < file path
    eg:mail-s" How old is yo U? "Root </etc/fstab
    

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If the host name of the current host is not www.magedu.com, change it to www.magedu.com
[' houstname '! = ' www.magedu.com '] && houstname www.magedu.com
If the host name of the current host is localhost, change it to www.magedu.com
[' houstname ' = = ' Localhoust '] && houstname www.magedu.com
If the host name of the current host is empty, or (none), or localhost, change it to www.magedu.com
[-Z ' hostname '] | | [' hostname ' = = ' n (none) '-o ' houstname ' = = ' localhoust '] && hostname www.magedu.com


Generate random numbers
RANDOM: 0-32768
Random number generator
/dev/random: The user process is blocked
/dev/urandom: Simulation generates random numbers
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Write a script that generates 10 random numbers using random and finds the maximum value.
#!/bin/bash
#
Declare-i max=0
Declare-i min=0
For I in {1..10}; Do
Myrand= $RANDOM
[$I-eq 1] && min= $MYRAND
If [$I-le 9]; Then
Echo-n "$MYRAND,"
Else
echo "$MYRAND"
Fi
[$MYRAND-gt $MAX] && max= $MYRAND
[$MYRAND-lt $MIN] && min= $MYRAND
Done
Echo $MAX, $MIN

Control structure:
Sequential structure
Select structure
If statement
Case statement
Case SWITCH in
value1)//switch value of 1
Statement1
...
;; Be sure to ";;" End
value2)//switch value of 2
Statement2
...
;;
*)//any value
Statement
...
;;
Esac
Loop structure

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Write a script that accepts options and parameters, and then gets the information for each option and parameter;
And can be based on options and parameters to make a specific operation
For example: adminusers.sh--add Tom,jerry
--del Tom,blair
-v|--verbose-h|--help

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Terminal type:
Console: Control Panel (directly connected to the display interface of the hardware device)
Pty: Physical terminal (VGA graphics)
TTY: Virtual Console (VGA)
ttys#: Serial Terminal
pts/#: Pseudo Terminal

This article is from the "11160930" blog, please be sure to keep this source http://11170930.blog.51cto.com/11160930/1773670

2016-5-15 Linux Basic Learning--case statement