Common linux commands (for personal use)

After using some commands in linux, I don't remember. Here I will take a note of my linux commands. I hope this article will be helpful to you.

View Disks
Df-h
View the file folder size in the current directory.
Du-sh *

View system cpu
Top and press "1" to view the number of cpu Cores
Free-m to check the memory size.

View the handle occupied by the 2743 thread
/Usr/sbin/lsof-p 2743
/Usr/sbin/lsof-p 2743 | grep del | wc-l: the number of del characters contained in the process-related modules.
Wc is statistics
-L: How many lines?-c: How many characters are contained?

Check the number of handles occupied by threads in the system. And corresponding thread number
/Usr/sbin/lsof-n | awk '{print $2}' | sort | uniq-c | sort-nr | more
View the details of a thread number.
Ps-aef | grep 24204

File Storage path occupied by NO release handle
Log on to cd/proc with the root permission
Ls displays the directories named by all process numbers.
Find the corresponding process to enter
Cd fd
Ls
A flickering file marked as deleted.

Cause of not releasing the handle: The first thread opens the file. Another thread deletes the file. The problem occurs. Kill the entire process to release all handles.

Grep ERROR stdout. log | more-c view ERROR log
Grep ERROR stdout. log. *-c

Obtain the port occupied by a thread
Netstat-anp | grep 13755

Check whether a port is occupied
Netstat-a | grep 14444

The isysearch user can log on to the root user. (Added functions)
Sudo su-root

Log on to mysql
Mysql-u username-p

Vi does not support Chinese characters.
Solution: In the esc status: set encoding = UTF-8
But it can only be used in the current window.
If the user is always valid, the user's home directory must be used again.
Vim. vimrc
Type set encoding = UTF-8.

View host uname-
Reboot

Stress tool thread ps-ef | grep JM

View the number of files in a folder, including files in subfolders.
Ls-lR | grep "^-" | wc-l
View the number of folders in a folder, including those in subfolders.
Ls-lR | grep "^ d" | wc-l

The-I option of grep indicates case-insensitive

Vi to the last line]
Vi jump to the first line [[
Vi jump to the beginning of the line $
Vi jump to the end of the row ^

Df-m is displayed as M
Df-h is displayed as G

Folder Link
Ln-s/home/support/nosql_data # nosql_data points to another directory
Delete
Rm nosql_data

Display the row number when viewing the file
Nl a.txt

Modify the folder owner
Chown-R username/dir: Call dir to the username user.

View disk io
Vmstat 1 100

Ll-t sort by the latest time

Send the variables in ssh to the script for Division calculation. Decimal places are allowed.
A = 2
B = 4
Echo $ a, $ B | awk-F "," '{print $1/$2 }'

Pass the script result to the variable in ssh (included with the 'sign)
L10 = 'grep "$ TODAY" $ FILE_PATH_STROE_GET | wc-l'

Show all restrictions on the host
Ulimit-