Check the size of the folder
du -h /home/oracle11_7/MainSoftCache/
View the number of files in a folder
ls -l |grep "^-" | wc -l
delete everything under the folder
rm -rf /home/oracle11_7/MainSoftCache/*
When there are too many files, an error rm will be reported: Argument list too long
Use this command ls | xargs -n 10 rm -fr ls means to output all file names (separated by spaces) xargs is to group the output of ls, every 10 as a group (separated by spaces), as rm -rf The parameter means that all file names are grouped by 10 and deleted by rm -rf
Check CPU usage
First execute top -u username
Then press number key 1
View java process
ps -ef | grep java
View the resource usage of each process (sorted by rsz as the actual memory from large to small)
ps -e -o 'pid,comm,args,pcpu,rsz,vsz,stime,user,uid' | grep oracle | sort -nrk5
open port number
iptables -I INPUT -p tcp --dport 8100 -j ACCEPT
service iptables save
service iptables restart iptables
View port list
lsof -i:80
iptables -L INPUT --line-numbers
Recursively authorize folders
chmod -Rf 777 oracle /home/oracle/Oracle/Middleware/
Delete mistyped characters in command mode
Ctrl+Backspace
rpm command
rpm -ivh package name
Install the package and display the installation progress.
Turn firewall on and off
Temporary effective, restore after restart
开启： service iptables start
关闭： service iptables stop
永久性生效，重启后不会复原
开启： chkconfig iptables on
关闭： chkconfig iptables off