压缩的概念

​
什么是压缩包？

就是一个特殊的文件，将多个文件或者目录压缩成一个特殊的文件  
​
​
为什么要用压缩包？
​
    减少占用的空间  
    
    加快传输的速度
​
​
windows：
​
    .zip      .rar
    
linux:
​
    .zip    .gz    .tar.gz      
​
​
如果要想Windows和linux中的压缩包互相使用，建议使用.zip种类的压缩包 
​
​
在Linux中压缩包的类型
​
​
.zip        #根据zip命令进行打包压缩的
​
.gz         #通过gzip命令进行压缩  只压缩文件，也会删除源文件 
​
.bz2        #通过bzip进行压缩， 只压缩文件，也会删除源文件
​
.tar.gz     #使用tar命令归档打包，然后使用gzip命令进行压缩 
​
.tar.bz2        #使用tar命令归档打包，然后使用bzip命令进行压缩  
​
​

zip命令

     zip      #可以对文件和目录进行打包，需要指定压缩包的名称 ​[root@qls ~]# yum install -y zip unzip

​
zip     #压缩的命令
​
选项：
​
        -r      #压缩目录 
        
        -q      #静默输出，不显示压缩的过程 
        
        

unzip   #解压zip格式的压缩包
​
选项：
​
        -l      #查看压缩包中的列表信息 
        
        -q      #静默输出，不显示解压的过程
        
        -d      #指定解压的目录
​

[root@qls ~]# ll
total 656
-rw-r--r-- 1 root root 670293 Jul 29 08:45 services
​
#针对文件进行压缩打包 
[root@qls ~]# zip  services.zip   services 
  adding: services (deflated 80%)
[root@qls ~]# ll
total 792
-rw-r--r-- 1 root root 670293 Jul 29 08:45 services
-rw-r--r-- 1 root root 136227 Jul 29 09:06 services.zip
​
​
#压缩目录时不加选项，只压缩目录本身 
[root@qls ~]# zip  etc.zip  /etc
  adding: etc/ (stored 0%)
[root@qls ~]# ll
total 796
-rw-r--r-- 1 root root    158 Jul 29 09:07 etc.zip
-rw-r--r-- 1 root root 670293 Jul 29 08:45 services
-rw-r--r-- 1 root root 136227 Jul 29 09:06 services.zip
[root@qls ~]# unzip  -l  etc.zip 
Archive:  etc.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
        0  07-29-2020 08:56   etc/
---------                     -------
        0                     1 file
[root@qls ~]# unzip  etc.zip 
Archive:  etc.zip
   creating: etc/
[root@qls ~]# ll
total 796
drwxr-xr-x 2 root root      6 Jul 29 08:56 etc
-rw-r--r-- 1 root root    158 Jul 29 09:07 etc.zip
-rw-r--r-- 1 root root 670293 Jul 29 08:45 services
-rw-r--r-- 1 root root 136227 Jul 29 09:06 services.zip
[root@qls ~]# ll etc
total 0
​
[root@qls ~]# zip  -r  etc.zip  /etc
[root@qls ~]# ll -h
total 13M
-rw-r--r-- 1 root root  12M Jul 29 09:10 etc.zip
-rw-r--r-- 1 root root 655K Jul 29 08:45 services
-rw-r--r-- 1 root root 134K Jul 29 09:06 services.zip
[root@qls ~]# du -sh  /etc
31M /etc
​
​
#查看压缩包里面的文件
[root@qls ~]# unzip -l  etc.zip
​
​
#静默输出 
[root@qls ~]# zip  -rq    etc1.zip  /etc
[root@qls ~]# ll
total 24976
-rw-r--r-- 1 root root 12380952 Jul 29 09:13 etc1.zip
-rw-r--r-- 1 root root 12380952 Jul 29 09:10 etc.zip
-rw-r--r-- 1 root root   670293 Jul 29 08:45 services
-rw-r--r-- 1 root root   136227 Jul 29 09:06 services.zip
​
​
#解压
[root@qls ~]# unzip   etc.zip
​
​
#静默解压文件，将文件解压到指定的目录下面
[root@qls ~]# unzip  -q  etc.zip   -d  /opt/
[root@qls ~]# ll /opt/
total 12
drwxr-xr-x 85 root root 8192 Jul 29 08:56 etc
-rw-r--r--  1 root root    0 Jul 28 12:09 file9
​
​
​

gzip命令​​​

gzip    #只能压缩文件，压缩文件的同时，会删除源文件，解压的时候，会删除压缩文件
​
选项：
​
    -d      #解压
    
    -r      #递归操作 
    
    
[root@qls ~]# ll
total 656
-rw-r--r-- 1 root root 670293 Jul 29 08:45 services
​
[root@qls ~]# gzip   services 
[root@qls ~]# ll
total 136
-rw-r--r-- 1 root root 136088 Jul 29 08:45 services.gz
​
​
#使用zcat命令查看gzip压缩的文件
[root@qls ~]# zcat  services.gz
​
​
#解压 
[root@qls ~]# gzip  -d  services.gz 
[root@qls ~]# ll
total 656
-rw-r--r-- 1 root root 670293 Jul 29 08:45 services
​
​
#将目录下的所有都进行压缩处理
[root@qls ~]# gzip  -r   /etc
​
​
#解压目录下的所有压缩包 
[root@qls ~]# gzip  -rd  /etc
​
​

bzip2命令

bzip2   #只能压缩文件，压缩文件的同时，会删除源文件，解压的时候，会删除压缩文件

选项：
 
  -d    #解压
​ 
  -k    #若要保留原始文件，请使用此参数  

[root@qls ~]# yum  install  -y  bzip2
​
#压缩
[root@qls ~]# bzip2  services 
[root@qls ~]# ll
total 124
-rw-r--r-- 1 root root 123932 Jul 29 08:45 services.bz2
​
#解压 
[root@qls ~]# bzip2  -d  services.bz2 
[root@qls ~]# ll
total 656
-rw-r--r-- 1 root root 670293 Jul 29 08:45 services
​
​
#查看bzip2压缩的文件
[root@qls ~]# bzcat   services.bz2 
​

 

tar命令​不负责压缩，只负责归档打包​​

    选项​   

      z       #使用gzip格式进行压缩 

      j       #使用bzip2格式进行压缩

 

    J       #使用xz格式进行压缩       
    
    c       #创建压缩包 
    
    v       #显示过程 
    
    f       #指定压缩包的名称 
    
    
    czf     #打包压缩  tar.gz格式的压缩包 
    
    cjf     #打包压缩 tar.bz2格式的压缩包         了解
    
    cJf     #打包压缩 tar.xz格式的压缩包          了解 
    
    t       #查看压缩中的内容 
    
    tf      #指定要查看的压缩包名称 
    
    x       #解压
    
    xf      #解压指定的压缩包 
    
    -C      #解压到指定的目录 
    
    h       #打包软连接的真实路径
    
    P       #使用绝对路径打包 
    
    X       #指定排除文件的列表文件
    
    --exclude=      #指定排除的文件
    
    --exclude-from=     #指定排除文件的列表
    
    
    
[root@qls ~]# ll
total 656
-rw-r--r-- 1 root root 670293 Jul 29 09:47 services
[root@qls ~]# tar  czf  services.tar.gz   services 
[root@qls ~]# ll
total 792
-rw-r--r-- 1 root root 670293 Jul 29 09:47 services
-rw-r--r-- 1 root root 136200 Jul 29 09:48 services.tar.gz
​
[root@qls ~]# tar  cjf  services.tar.bz2  services
[root@qls ~]# ll
total 916
-rw-r--r-- 1 root root 670293 Jul 29 09:47 services
-rw-r--r-- 1 root root 124166 Jul 29 09:48 services.tar.bz2
-rw-r--r-- 1 root root 136200 Jul 29 09:48 services.tar.gz
[root@qls ~]# tar  cJf  services.tar.xz  services
[root@qls ~]# ll
total 1016
-rw-r--r-- 1 root root 670293 Jul 29 09:47 services
-rw-r--r-- 1 root root 124166 Jul 29 09:48 services.tar.bz2
-rw-r--r-- 1 root root 136200 Jul 29 09:48 services.tar.gz
-rw-r--r-- 1 root root 100640 Jul 29 09:49 services.tar.xz
​
[root@qls ~]# tar  czf  etc.tar.gz   /etc
tar: Removing leading `/' from member names     #删根的操作是正常的
[root@qls ~]# ll
total 10952
-rw-r--r-- 1 root root 10171684 Jul 29 09:56 etc.tar.gz
​
​
​
[root@qls ~]# tar  tf  services.tar.gz 
services
​
​
​
[root@qls ~]# tar  xf  services.tar.gz 
[root@qls ~]# ll
total 10952
-rw-r--r-- 1 root root 10171684 Jul 29 09:56 etc.tar.gz
-rw-r--r-- 1 root root   670293 Jul 29 09:47 services
-rw-r--r-- 1 root root   124166 Jul 29 09:48 services.tar.bz2
-rw-r--r-- 1 root root   136200 Jul 29 09:48 services.tar.gz
-rw-r--r-- 1 root root   100640 Jul 29 09:49 services.tar.xz
[root@qls ~]# tar xf  etc.tar.gz 
[root@qls ~]# ll
total 10964
drwxr-xr-x 77 root root     8192 Jul 29 08:56 etc
-rw-r--r--  1 root root 10171684 Jul 29 09:56 etc.tar.gz
-rw-r--r--  1 root root   670293 Jul 29 09:47 services
-rw-r--r--  1 root root   124166 Jul 29 09:48 services.tar.bz2
-rw-r--r--  1 root root   136200 Jul 29 09:48 services.tar.gz
-rw-r--r--  1 root root   100640 Jul 29 09:49 services.tar.xz
​
​
[root@qls ~]# tar  cjf  etc.tar.bz2   /etc
tar: Removing leading `/' from member names
[root@qls ~]# tar  cJf  etc.tar.xz   /etc
tar: Removing leading `/' from member names
[root@qls ~]# ll
total 26808
-rw-r--r-- 1 root root  8994047 Jul 29 10:01 etc.tar.bz2
-rw-r--r-- 1 root root 10171684 Jul 29 09:56 etc.tar.gz
-rw-r--r-- 1 root root  7238084 Jul 29 10:01 etc.tar.xz
-rw-r--r-- 1 root root   670293 Jul 29 09:47 services
-rw-r--r-- 1 root root   124166 Jul 29 09:48 services.tar.bz2
-rw-r--r-- 1 root root   136200 Jul 29 09:48 services.tar.gz
-rw-r--r-- 1 root root   100640 Jul 29 09:49 services.tar.xz
[root@qls ~]# tar  xf  etc.tar.bz2      #解压的时候，自动识别压缩包的格式 
[root@qls ~]# ll
total 26820
drwxr-xr-x 77 root root     8192 Jul 29 08:56 etc
-rw-r--r--  1 root root  8994047 Jul 29 10:01 etc.tar.bz2
-rw-r--r--  1 root root 10171684 Jul 29 09:56 etc.tar.gz
-rw-r--r--  1 root root  7238084 Jul 29 10:01 etc.tar.xz
​
​
[root@qls ~]# tar  xf  etc.tar.gz   -C  /opt/
[root@qls ~]# ll /opt/
total 668
drwxr-xr-x 77 root root   8192 Jul 29 08:56 etc
-rw-r--r--  1 root root 670293 Jul 29 09:47 services
​
​#显示打包过程
[root@qls ~]# tar czvf  etc.tar.gz   /etc
​
​#显示解压过程
[root@qls ~]# tar  xvf  etc.tar.gz 
​
​
[root@qls ~]# ll  /bin  -d
lrwxrwxrwx. 1 root root 7 Jul  6 02:13 /bin -> usr/bin
[root@qls ~]# tar  czf  bin.tar.gz  /bin
tar: Removing leading `/' from member names
[root@qls ~]# ll
total 9952
-rw-r--r--  1 root root      110 Jul 29 10:14 bin.tar.gz
drwxr-xr-x 77 root root     8192 Jul 29 08:56 etc
-rw-r--r--  1 root root 10171684 Jul 29 10:04 etc.tar.gz
[root@qls ~]# tar xf  bin.tar.gz 
[root@qls ~]# ll
total 9952
lrwxrwxrwx  1 root root        7 Jul  6 02:13 bin -> usr/bin
-rw-r--r--  1 root root      110 Jul 29 10:14 bin.tar.gz
drwxr-xr-x 77 root root     8192 Jul 29 08:56 etc
-rw-r--r--  1 root root 10171684 Jul 29 10:04 etc.tar.gz
​
​
​#打包软链接的真实路径
[root@qls ~]# tar  czhf  bin1.tar.gz  /bin
tar: Removing leading `/' from member names
tar: Removing leading `/' from hard link targets
[root@qls ~]# ll
total 36880
lrwxrwxrwx  1 root root        7 Jul  6 02:13 bin -> usr/bin
-rw-r--r--  1 root root 27573768 Jul 29 10:16 bin1.tar.gz
-rw-r--r--  1 root root      110 Jul 29 10:14 bin.tar.gz
drwxr-xr-x 77 root root     8192 Jul 29 08:56 etc
-rw-r--r--  1 root root 10171684 Jul 29 10:04 etc.tar.gz
​
​
​
#打包的时候有个删根的操作   怎么避免这个删根的操作 
​
#第一种   使用相对路径打包 
​
[root@qls ~]# cd  /  
[root@qls /]# tar  czf  /root/etc1.tar.gz    etc
[root@qls /]# ll /root
total 46852
dr-xr-xr-x  2 root root    20480 Jul 29 08:58 bin
-rw-r--r--  1 root root 27573768 Jul 29 10:16 bin1.tar.gz
-rw-r--r--  1 root root      110 Jul 29 10:14 bin.tar.gz
drwxr-xr-x 77 root root     8192 Jul 29 08:56 etc
-rw-r--r--  1 root root 10171684 Jul 29 10:19 etc1.tar.gz
-rw-r--r--  1 root root 10171684 Jul 29 10:04 etc.tar.gz
​
#真实打包场景 
​
[root@qls ~]# cd  /  &&  tar  czf  /root/etc3.tar.gz   etc  &&  cd  -
/root
[root@qls ~]# ll
total 581012
dr-xr-xr-x  2 root root     20480 Jul 29 08:58 bin
-rw-r--r--  1 root root  27573768 Jul 29 10:16 bin1.tar.gz
-rw-r--r--  1 root root       110 Jul 29 10:14 bin.tar.gz
drwxr-xr-x 77 root root      8192 Jul 29 08:56 etc
-rw-r--r--  1 root root  10171684 Jul 29 10:19 etc1.tar.gz
-rw-r--r--  1 root root 347209728 Jul 29 10:22 etc2.tar.gz
-rw-r--r--  1 root root  10171684 Jul 29 10:22 etc3.tar.gz
​
​
#第二种方法   使用绝对路径打包    告诉系统不要删根 
​
#使用绝对路径打包 
[root@qls ~]# tar  czPf  etc4.tar.gz   /etc
​
#使用绝对路经解压 
[root@qls ~]# tar xPf  etc4.tar.gz
​
​
[root@qls ~]# cat  /etc/services  >> /opt/services 
[root@qls ~]# ll /opt/
total 1744
drwxr-xr-x 77 root root    8192 Jul 29 08:56 etc
-rw-r--r--  1 root root     158 Jul 29 10:28 hosts
-rw-r--r--  1 root root 1340586 Jul 29 10:29 services
[root@qls ~]# tar xPf  opt.tar.gz 
[root@qls ~]# ll /opt/
total 672
drwxr-xr-x 77 root root   8192 Jul 29 08:56 etc
-rw-r--r--  1 root root    158 Jul 29 10:28 hosts
-rw-r--r--  1 root root 670293 Jul 29 09:47 services
​
​
#排除不需要打包的文件
[root@qls ~]# tar czf  etc1.tar.gz  /etc
tar: Removing leading `/' from member names
[root@qls ~]# ll
total 9936
-rw-r--r-- 1 root root 10171949 Jul 29 10:51 etc1.tar.gz
[root@qls ~]# ll /etc/services 
-rw-r--r-- 1 root root 670293 Jun  7  2013 /etc/services
[root@qls ~]# tar  czf  etc2.tar.gz   --exclude=/etc/services   /etc
tar: Removing leading `/' from member names
[root@qls ~]# ll
total 19740
-rw-r--r-- 1 root root 10171949 Jul 29 10:51 etc1.tar.gz
-rw-r--r-- 1 root root 10036635 Jul 29 10:52 etc2.tar.gz
[root@qls ~]# tar tf  etc2.tar.gz  |  grep  services
etc/firewalld/services/
​
​
#排除多个文件
[root@qls ~]# tar czf  etc3.tar.gz  --exclude=/etc/services  --exclude=/etc/passwd  /etc
tar: Removing leading `/' from member names
[root@qls ~]# ll
total 29544
-rw-r--r-- 1 root root 10171949 Jul 29 10:51 etc1.tar.gz
-rw-r--r-- 1 root root 10036635 Jul 29 10:52 etc2.tar.gz
-rw-r--r-- 1 root root 10035297 Jul 29 10:54 etc3.tar.gz
[root@qls ~]# tar tf  etc3.tar.gz  | grep  -E  'services|passwd'
etc/security/opasswd
etc/passwd-
etc/pam.d/passwd
etc/firewalld/services/
​
​
[root@qls ~]# tar czf  etc4.tar.gz  --exclude=/etc/{services,passwd}   /etc
tar: Removing leading `/' from member names
[root@qls ~]# ll
total 39348
-rw-r--r-- 1 root root 10171949 Jul 29 10:51 etc1.tar.gz
-rw-r--r-- 1 root root 10036635 Jul 29 10:52 etc2.tar.gz
-rw-r--r-- 1 root root 10035297 Jul 29 10:54 etc3.tar.gz
-rw-r--r-- 1 root root 10035297 Jul 29 10:55 etc4.tar.gz
​
​
[root@qls ~]# cat paichu.list
/etc/fstab
/etc/group
/etc/hosts
/etc/passwd
/etc/services
[root@qls ~]# tar czfX   etc5.tar.gz   paichu.list    /etc
tar: Removing leading `/' from member names
[root@qls ~]# ll 
total 49152
-rw-r--r-- 1 root root 10171949 Jul 29 10:51 etc1.tar.gz
-rw-r--r-- 1 root root 10036635 Jul 29 10:52 etc2.tar.gz
-rw-r--r-- 1 root root 10035297 Jul 29 10:54 etc3.tar.gz
-rw-r--r-- 1 root root 10035297 Jul 29 10:55 etc4.tar.gz
-rw-r--r-- 1 root root 10033927 Jul 29 10:58 etc5.tar.gz
-rw-r--r-- 1 root root       59 Jul 29 10:57 paichu.list
​
​
​
​
[root@qls ~]# tar tf etc5.tar.gz  | grep  -Ew  'fstab|group|hosts|passwd|services'
etc/security/group.conf
etc/group-
etc/passwd-
etc/hosts.allow
etc/hosts.deny
etc/pam.d/passwd
etc/iproute2/group
etc/firewalld/services/
​
​
​
[root@qls ~]# tar  czf  etc6.tar.gz   --exclude-from=paichu.list   /etc
tar: Removing leading `/' from member names
[root@qls ~]# ll
total 58952
-rw-r--r-- 1 root root 10171949 Jul 29 10:51 etc1.tar.gz
-rw-r--r-- 1 root root 10036635 Jul 29 10:52 etc2.tar.gz
-rw-r--r-- 1 root root 10035297 Jul 29 10:54 etc3.tar.gz
-rw-r--r-- 1 root root 10035297 Jul 29 10:55 etc4.tar.gz
-rw-r--r-- 1 root root 10033927 Jul 29 10:58 etc5.tar.gz
-rw-r--r-- 1 root root 10033927 Jul 29 11:01 etc6.tar.gz
-rw-r--r-- 1 root root       59 Jul 29 10:57 paichu.list
​
​
​

tar命令与find结合​

[root@qls ~]# tar  czf  log1.tar.gz   `find  /var/log/  -type f  -name "*.log"`
tar: Removing leading `/' from member names
[root@qls ~]# tar  czf  log2.tar.gz   $(find  /var/log/  -type f  -name "*.log")
tar: Removing leading `/' from member names


# xargs   把find命令查找出来的文件统一的赋值给了后面 

[root@qls ~]# find  /var/log/  -type f  -name "*.log"  -exec  tar czf  log3.tar.gz  {}  ;
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names
tar: Removing leading `/' from member names



# 当使用-exec时，  把find查找的文件是进行一个个赋值给{}的 

[root@qls ~]# find  /var/log/  -type f  -name "*.log"  | xargs  tar czf   log4.tar.gz  

tar: Removing leading `/' from member name​

​

[root@qls ~]# ll
total 916
-rw-r--r-- 1 root root 309155 Jul 29 11:09 log1.tar.gz
-rw-r--r-- 1 root root 309155 Jul 29 11:09 log2.tar.gz
-rw-r--r-- 1 root root    356 Jul 29 11:10 log3.tar.gz
-rw-r--r-- 1 root root 309155 Jul 29 11:10 log4.tar.gz
​
[root@qls ~]# tar tf  log1.tar.gz   
var/log/tuned/tuned.log
var/log/audit/audit.log
var/log/anaconda/anaconda.log
var/log/anaconda/X.log
var/log/anaconda/program.log
var/log/anaconda/packaging.log
var/log/anaconda/storage.log
var/log/anaconda/ifcfg.log
var/log/anaconda/ks-script-3PCKae.log
var/log/anaconda/journal.log
var/log/boot.log
var/log/vmware-vmsvc.log
var/log/vmware-network.8.log
var/log/vmware-network.5.log
var/log/vmware-network.2.log
var/log/vmware-network.7.log
var/log/vmware-network.4.log
var/log/vmware-network.1.log
var/log/test.log
var/log/yum.log
var/log/vmware-network.9.log
var/log/nginx/error.log
var/log/nginx/access.log
var/log/vmware-network.6.log
var/log/vmware-network.3.log
var/log/vmware-network.log
[root@qls ~]# tar tf  log3.tar.gz   
var/log/vmware-network.log
​
​

​
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date命令

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#显示系统时间 
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[root@qls ~]# date
Wed Jul 29 11:19:19 CST 2020
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[root@qls ~]# date  +%Y     #世纪
2020
[root@qls ~]# date  +%y     #年代
20
[root@qls ~]# date  +%m     #月份
07
[root@qls ~]# date  +%d     #日期 
29
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[root@qls ~]# date  +%Y-%m-%d
2020-07-29
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[root@qls ~]# date +%F      #显示日期 
2020-07-29
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[root@qls ~]# date  +%y-%m-%d
20-07-29
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[root@qls ~]# date +%H      #时
11
[root@qls ~]# date +%M      #分
23
[root@qls ~]# date +%S      #秒
24
[root@qls ~]# date
Wed Jul 29 11:23:28 CST 2020
[root@qls ~]# date +%H:%M:%S
11:23:43
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[root@qls ~]# date +%T      #显示时间 
11:24:08
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[root@qls ~]# date +%F-%T
2020-07-29-11:24:34
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[root@qls ~]# date +%w      #周几
3
[root@qls ~]# date +%W      #今年第几周 
30
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[root@qls ~]# date +%s      #距离1970年1月1日0分0秒过来多少秒 
1595993167
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选项：
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    -d      #自定义日期 
    
    
    -s      #修改日期   时间 
    
    
    
[root@qls ~]# date +%F
2020-07-29
[root@qls ~]# date  -d  "-1 day"  +%F
2020-07-28
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[root@qls ~]# date  -d  "+1 day"  +%F
2020-07-30
[root@qls ~]# date  -d  "+1 month"  +%F
2020-08-29
[root@qls ~]# date  -d  "-1 month"  +%F
2020-06-29
[root@qls ~]# date  -d  "-1 year"  +%F
2019-07-29
[root@qls ~]# date  -d  "+1 year"  +%F
2021-07-29
​
​
[root@qls ~]# date
Wed Jul 29 11:31:42 CST 2020
[root@qls ~]# date  -s  20200730
Thu Jul 30 00:00:00 CST 2020
[root@qls ~]# date
Thu Jul 30 00:00:08 CST 2020
[root@qls ~]# date  -s  2020/07/29
Wed Jul 29 00:00:00 CST 2020
[root@qls ~]# date
Wed Jul 29 00:00:02 CST 2020
[root@qls ~]# date  -s  11:32:30
Wed Jul 29 11:32:30 CST 2020
[root@qls ~]# date
Wed Jul 29 11:32:31 CST 2020
[root@qls ~]# date  -s  "20200730  11:00:00"
Thu Jul 30 11:00:00 CST 2020
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#时间同步
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ntpdate
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[root@qls ~]# yum install ntpdate  -y 
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向时间服务器进行同步时间 
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ntp.aliyun.com   
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ntp1.aliyun.com   ....   ntp7.aliyun.com  
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[root@qls ~]# ntpdate   ntp.aliyun.com
29 Jul 11:36:33 ntpdate[31370]: step time server 203.107.6.88 offset -84415.000442 sec
[root@qls ~]# date
Wed Jul 29 11:36:35 CST 2020
[root@qls ~]# date  -s  20200730
Thu Jul 30 00:00:00 CST 2020
[root@qls ~]# ntpdate   ntp.aliyun.com
29 Jul 11:36:56 ntpdate[31392]: step time server 203.107.6.88 offset -44591.413933 sec
[root@qls ~]# date
Wed Jul 29 11:37:02 CST 2020
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