Linux Common Command logging

ls command:

1. Ls-1: Displays the files in this directory in one line
2. Ls-a: Show hidden files
3. LS/: View something under the root path
4. Ls-r/: Recursively view all content under the root path
5. Ls-s: Display size
6. Ls-alsh: Show the size of each file in the form of human understanding, specific to K
7. LS--help: If the option is a word, or multiple letters for a whole as a command option, the front to add 2 bars
8. LS-T: Display in reverse order of file modification time
9. Ls-i: Ignore ....
10. Ls-l--TIME=ATIME/HOME/LIUSHU/PRAC/AA Show access time for content under the AA folder
11. Ls-l--TIME=CTIME/HOME/LIUSHU/PRAC/AA Displays the creation time of content under the AA folder

ls-l command in detail: The results of a total of 7 columns, the following respectively describe the meaning of the following columns:

1. Second column: The number of hard links representing the file
2. Third column: Represents the owner of the file
3. Column Fourth: Represents the group in which the file resides
4. The Fifth column: represents the size of the file, byte size, after LS-LH plus h parameter, can be more user-friendly display file size
5. The sixth column: The time stamp that represents the file, the time that was created or last modified
6. Column seventh: Name representing the file
7. First column:
8. 1) The first character of the first column-: ordinary file; d: directory (folder); B: Device files (block files-devices that can store things, such as: U disk, hard disk, disk, etc.); C: Device file (character file-cannot store device such as TTY, terminal, keyboard, mouse, monitor, etc.); L: Shortcuts (soft links)
9. 2) XXX yyy zzz:xxx--owner's permission, yyy--the owner's group, zzz--other people's rights
10. 3) rwx:r--read Read permission, w--write write permission, X--execute executable permission, the relevant location is-------no permission
11. 4) 7=4+2+1 (4:read; 2:write; 1:execute)
12. 5) Execute: For a text file, an executable permission; for a folder, the permission to have a CD to that folder

pwd: Print the current pathchmod:

1. Give permission to Ugo +/-/=; comma-delimited, comma-preceded and trailing spaces; a (all) = = = Ugo

2. chmod 777 Aa.txt

chmod- R 777 AA-- recursion changes permissions that include the contents of the AA folder itself and its folders (Note: AA is a folder and there is a AA file under the AA folder), such as:

1. mkdir AA
2. CD AA
3. Touch AA
4. Ls-l AA: View specific information for files under the AA folder
5. Ls-ld aa: Check the specific information of the AA for this folder itself
6. Chmod-r 744 AA

Chown: Changing the file owner and group

1. Useradd Tom---Add a new Tom user
2. Chown Tom Aa.txt---Change the owner of Aa.txt to Tom
3. Chown tom:root aa.txt---Change the owner of the Aa.txt to Tom and change the group to the root group
4. Chown tom.root aa.txt---Change the owner of the Aa.txt to Tom and change its group to the root group (3 and 4 have the same effect, and the owner and the group are separated by: or.)
5. Chown-r root:root AA---Change the AA file and the owner of the file below to root and the same group as root

CHGRP: Changing the group in which files are located

1. CHGRP Root Aa.txt---Change the group of Aa.txt to root
2. CHGRP-R root AA---Change the AA file and the group under which it resides to root

File: View the type of files: The name of the File+ file (folder) Clear-screen command:

1. Clear
2. Shortcut keys: Ctrl + L

Date--help usage: date [options] ... [+ format] or: Date [-u|--utc|--universal] [MMDDHHMM[[CC]YY][.SS]] Displays the current time in the given format, or sets the system date. Date command: The day is 2016-06-30 23:56:38

1. Date +%y--shows the full 4 bits of the current year, such as: 2016
2. The date +%y--shows the following 2 bits of the current year, such as: 16
3. Date +%m--shows the current month, such as: 6
4. Date +%m--shows the current score as: 56
5. Date mmddhhmm--Setting the current system time
6. Date command, change the display format date + '%y%m%d-%h:%m:%s ' (use this command to automatically get the current time when you back up the database or the log requires a timestamp)

Cal command: Used to display the calendar

1. cal--shows this month's calendar.
2. Cal 2016--shows the calendar for all months of the year
3. Cal M Y--cal followed by month and then with year--cal 12 2016--show December 2016, this month's calendar

BC Command: Calculator

1. Bc
2. Usage: Execute BC
3. Then enter the number to be calculated, such as 1/3 to get 0 on another line
4. Setting accuracy: scale=4
5. Quit: Quit

Linux Common Command logging