content
grep filter directives and pipe symbols |
time date class
date display time command
Basic syntax:
date (display current time)
date +%Y (display current year)
date +%m (display current month)
date +%d (displays the current day)
date " +%Y-%m-%d %H:%M:%S" (display year, month, day, hour, minute, second)
Example: Demonstrate the above command
[root@kongchao02 myroot]# date
2022年 03月 05日 星期六 09:01:17 CST
[root@kongchao02 myroot]# date +%Y
2022
[root@kongchao02 myroot]# date +%m
03
[root@kongchao02 myroot]# date +%d
05
[root@kongchao02 myroot]#
[root@kongchao02 myroot]# date "+%Y-%m-%d %H:%M:%S"
2022-03-05 09:03:25
[root@kongchao02 myroot]#
set date command
Basic syntax: date -s string time
The example sets the current time of the system,
[root@kongchao02 myroot]# date
2022年 03月 05日 星期六 09:07:55 CST
[root@kongchao02 myroot]# date -s "2022-3-5 09:07:00"
2022年 03月 05日 星期六 09:07:00 CST
[root@kongchao02 myroot]# date
2022年 03月 05日 星期六 09:07:05 CST
[root@kongchao02 myroot]#
cal show calendar
View Calendar Instructions cal
Basic syntax: cal [options] (display this month's calendar without options)
View a calendar for a year such as 2022, cal 2022
Example 1, display the current month cal
[root@kongchao02 myroot]# cal
三月 2022
日 一 二 三 四 五 六
1 2 3 4 5
6 7 8 9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30 31
[root@kongchao02 myroot]#
Example 2: Display 2022 calendar cal 2022
[root@kongchao02 myroot]# cal 2022
2022
一月 二月 三月
日 一 二 三 四 五 六 日 一 二 三 四 五 六 日 一 二 三 四 五 六
1 1 2 3 4 5 1 2 3 4 5
2 3 4 5 6 7 8 6 7 8 9 10 11 12 6 7 8 9 10 11 12
9 10 11 12 13 14 15 13 14 15 16 17 18 19 13 14 15 16 17 18 19
16 17 18 19 20 21 22 20 21 22 23 24 25 26 20 21 22 23 24 25 26
23 24 25 26 27 28 29 27 28 27 28 29 30 31
30 31
四月 五月 六月
日 一 二 三 四 五 六 日 一 二 三 四 五 六 日 一 二 三 四 五 六
1 2 1 2 3 4 5 6 7 1 2 3 4
3 4 5 6 7 8 9 8 9 10 11 12 13 14 5 6 7 8 9 10 11
10 11 12 13 14 15 16 15 16 17 18 19 20 21 12 13 14 15 16 17 18
17 18 19 20 21 22 23 22 23 24 25 26 27 28 19 20 21 22 23 24 25
24 25 26 27 28 29 30 29 30 31 26 27 28 29 30
七月 八月 九月
日 一 二 三 四 五 六 日 一 二 三 四 五 六 日 一 二 三 四 五 六
1 2 1 2 3 4 5 6 1 2 3
3 4 5 6 7 8 9 7 8 9 10 11 12 13 4 5 6 7 8 9 10
10 11 12 13 14 15 16 14 15 16 17 18 19 20 11 12 13 14 15 16 17
17 18 19 20 21 22 23 21 22 23 24 25 26 27 18 19 20 21 22 23 24
24 25 26 27 28 29 30 28 29 30 31 25 26 27 28 29 30
31
十月 十一月 十二月
日 一 二 三 四 五 六 日 一 二 三 四 五 六 日 一 二 三 四 五 六
1 1 2 3 4 5 1 2 3
2 3 4 5 6 7 8 6 7 8 9 10 11 12 4 5 6 7 8 9 10
9 10 11 12 13 14 15 13 14 15 16 17 18 19 11 12 13 14 15 16 17
16 17 18 19 20 21 22 20 21 22 23 24 25 26 18 19 20 21 22 23 24
23 24 25 26 27 28 29 27 28 29 30 25 26 27 28 29 30 31
30 31
[root@kongchao02 myroot]#
search find class
find command
The find command will recursively traverse its subdirectories from the specified directory downward, and display the files or directories that meet the conditions on the terminal
Basic syntax: find [search scope] [options]
Option Description:
| Options | Function |
| -name <query method> | Find pattern files by specified filename |
| -user<username> | Find all files belonging to the specified username |
| -size <file size> | Find files by specified file size |
Example 1: Find by file name , find hello.txt under /home
[root@kongchao02 ~]# find /home -name hello.txt
/home/hello.txt
[root@kongchao02 ~]#
Example 2: Find kc user in /home by owner
[root@kongchao02 /]# ls /home
hello1.txt hello.txt kc kongchao kongchao1 kongchao2
[root@kongchao02 /]# find /home -user kc
/home/kc
/home/kc/.mozilla
/home/kc/.mozilla/plugins
/home/kc/.mozilla/extensions
/home/kc/.bash_profile
/home/kc/.bash_logout
/home/kc/.bashrc
[root@kongchao02 /]#
Example 3: Find by size , find files larger than 100M in the entire linux system (+n is greater than -n is less than n equal, the unit is k, M, G)
[root@kongchao02 ~]# find / -size +100M
/sys/devices/pci0000:00/0000:00:0f.0/resource1_wc
/sys/devices/pci0000:00/0000:00:0f.0/resource1
/proc/kcore
find: ‘/proc/6122/task/6122/fd/5’: 没有那个文件或目录
find: ‘/proc/6122/task/6122/fdinfo/5’: 没有那个文件或目录
find: ‘/proc/6122/fd/6’: 没有那个文件或目录
find: ‘/proc/6122/fdinfo/6’: 没有那个文件或目录
/var/cache/yum/x86_64/7/updates/packages/firefox-91.6.0-1.el7.centos.x86_64.rpm
/var/lib/rpm/Packages
/run/media/root/CentOS 7 x86_64/LiveOS/squashfs.img
/usr/lib/locale/locale-archive
/usr/lib64/firefox/libxul.so
[root@kongchao02 ~]#
ls -lh visual display
ls -lh displays in human form
[root@kongchao02 ~]# ls -l
总用量 40
-rw-------. 1 root root 1834 2月 28 19:57 anaconda-ks.cfg
-rw-r--r--. 1 root root 1865 2月 28 19:59 initial-setup-ks.cfg
drwxr-xr-x. 2 root root 4096 2月 28 20:00 公共
drwxr-xr-x. 2 root root 4096 2月 28 20:00 模板
drwxr-xr-x. 2 root root 4096 2月 28 20:00 视频
drwxr-xr-x. 2 root root 4096 2月 28 20:00 图片
drwxr-xr-x. 2 root root 4096 2月 28 20:00 文档
drwxr-xr-x. 2 root root 4096 2月 28 20:00 下载
drwxr-xr-x. 2 root root 4096 2月 28 20:00 音乐
drwxr-xr-x. 2 root root 4096 3月 1 21:09 桌面
[root@kongchao02 ~]# ls -lh
总用量 40K
-rw-------. 1 root root 1.8K 2月 28 19:57 anaconda-ks.cfg
-rw-r--r--. 1 root root 1.9K 2月 28 19:59 initial-setup-ks.cfg
drwxr-xr-x. 2 root root 4.0K 2月 28 20:00 公共
drwxr-xr-x. 2 root root 4.0K 2月 28 20:00 模板
drwxr-xr-x. 2 root root 4.0K 2月 28 20:00 视频
drwxr-xr-x. 2 root root 4.0K 2月 28 20:00 图片
drwxr-xr-x. 2 root root 4.0K 2月 28 20:00 文档
drwxr-xr-x. 2 root root 4.0K 2月 28 20:00 下载
drwxr-xr-x. 2 root root 4.0K 2月 28 20:00 音乐
drwxr-xr-x. 2 root root 4.0K 3月 1 21:09 桌面
[root@kongchao02 ~]#
locate locate file path
locate command
The locate command can quickly locate the file path. The locate command utilizes the pre-established locate database of all file names and paths in the system to quickly locate a given file. The Locate command does not need to traverse the entire file system, and the query speed is faster. In order to ensure the accuracy of the query results, the administrator must regularly update the locate time
Basic syntax: locate searches for files
Special Note
Since the locate command performs queries based on the database, you must use the updatedb command to create the locate database before running it for the first time . If the first lookup is not performed, it will not be retrieved
Application Example
Case 1: Please use the locate command to quickly locate the directory where the hello.txt file is located
[root@kongchao02 ~]# updatedb
[root@kongchao02 ~]# locate hello.txt
/home/hello.txt
[root@kongchao02 ~]#
which view command location
The which command can check which directory a command is in.
Basic syntax: the which directive
Example: Check which directory the ls and cd commands are in
[root@kongchao02 ~]# which ls
alias ls='ls --color=auto'
/usr/bin/ls
[root@kongchao02 ~]# which cd
/usr/bin/cd
[root@kongchao02 ~]#
grep filter directives and pipe symbols |
grep to filter the lookup. The pipe character " |" indicates that the output of the processing result of the previous command is passed to the subsequent command processing
Basic syntax: grep [options] find what source files
Common options:
| Options | Function |
| -n | Show matches and line numbers |
| -i | Ignore letter case |
Example: In the hello.txt file, check the line where "yes" is located, and display the line number
写法①：cat /home/hello.txt | grep -n "yes"
写法②：grep -n "yes" /home/hello.txt[root@kongchao02 /]# ls /home
hello.txt kc kongchao kongchao1 kongchao2
[root@kongchao02 /]# cat -n /home/hello.txt
1 hello world
2 yes
3 NO
4 are you ok
5 kongchao who is
6 yes
7
[root@kongchao02 /]# cat /home/hello.txt | grep -n "yes"
2:yes
6:yes
[root@kongchao02 /]# grep -n "yes" /home/hello.txt
2:yes
6:yes
[root@kongchao02 /]#
