1.
systemctl status servicename(httpd) It shows the
status of the service it started or stoped
2.
when
you start a service you must enable the service by systemctl
enable httpd
3.
systemctl start httpd
4.
when
you stop a service you must enable the service by systemctl
disable httpd
5.
systemctl stop httpd
6.
systemctl is-enabled apache2 it shows the enable or disable status
7.
after
that you restart the VM it will starts running
8.
systemctl
command is read the file is located in this location cd /etc/systemd/
in that directory find the file by typing command find . -name httpd* one file is there ./system/multi
user.target.wants/httpd.service This
file knows the how to start and stop the httpd service. It calls some binary
files it creates the processes that running in background
9.
ps aux command
is shows all the process running in your system sort with there usage all the
process owned by the root user
10.
PID 1 is
systemd this is the first process in linux
(redhat system) in ubuntu is init is the first process
11.
Systemd manages the other
process if it goes downb entire system goes down it manages the other process
12.
[kworker
/u4] square boxe process are called kernel threads
13.
Other
columns are %cpu cpu utlise %mem memory utlise
14.
State S is for
sleaping R is for running
15.
Sshd service
is serve the ssh request
16.
top command
is like taskmanager used to show the dynamic process sort by the utilization
also shows the how long system is running
17.
load avg is
slowly increase slowly decrease is shows the status at 3 different values
Current load avg, last 5 mins, last 15 mins
18.
ps -ef It
shows pid and ppid process and parent process id
19.
ps -ef | grep httpd it shows the httpd process if you want to
stop the process pid 1 is started process of other processes to stop the
process by kill process id (kill 3284) command
20.
kill -9 3384 is forcefully killing the process parent is died and
child process is not killed is called arphon process
is called dead process. by remove this child process all at once ps -ef | grep httpd | grep -v ‘auto’ and ps -ef | grep httpd | grep -v ‘grep’ it
automatically kills the all the arphon process
21.
ps -ef | grep httpd | grep -v ‘auto’ | awk ‘{print $2}’ it shows the (awk
command) second field ps -ef | grep httpd | grep -v
‘auto’ | awk ‘{print $2}’ | xargs kill -9 It kill the all the processes
one by one automatically
22.
Arphon processes are the process if parent is dead and
chaild processes are still running
23.
Zombi
process is that is a dead its not serving any purpose but it is still there in
process table is coming from the kernel have a process table to clear this
process you will reboot the system other commands also there
24.
Arkaying is
nothing but compressing the data tar czvf
filename.tar.gz * (c- create,
z-compress, v-verfol print o/p, f-file) * current working directory
25.
for
unzip the tar arkying file tar xzvf filename.tar.gz it ectracts in current
location. For untar to some other location give location path tar xzvf filename.tar.gz -C /var/www/html it un
arkaye in to html location. Ex: tar xzvf
wave-cafe-website.tar.gz -C /var/www/html To know more options tar --help
26.
Zip is also a command to compress the files or
extract the files arkyee compared to zip
tar is the best one for zip the files typing command zip
-r filename.zip *(or file name) to un zip
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