Linux

connected (press CTRL_C to quit)
>{"action":"sendmessage", "data": "some msg num 1 "}
< "response from backend: <connectionid> "
>{"action":"sendmessage", "data": "some msg num 12"}
< "response from backend: <connectionid> "

set env Variable to Shell,system

To set variable only for current shell:

VARNAME="my value"

To set it for current shell and all processes started from current shell:

export VARNAME="my value" # shorter, less portable version

To set it permanently for all future bash sessions add such line to your .bashrc file in your $HOME directory.

To set it permanently, and system wide (all users, all processes) add set variable in /etc/environment:

sudo -H gedit /etc/environment

This file only accepts variable assignments like:

VARNAME="my value"

Do not use the export keyword here.

You need to logout from current user and login again so environment variables changes take place.

For example in userdata:

echo "JAVA_HOME=/jdk1.8.0_172" >> /etc/environment

This would add the JAVA_HOME=/jdk1.8.0_172 line to that file. Note, you should not use export inside that file.

The PATH variable is likely already defined in the /etc/environment file and you'll need to overwrite that appropriately if you are going to append additional paths to it.

Test connectivity 5sec time out on port 9011

nc -w 5 -v dbqlosbap01.us.dns.com 9011

aws elasticbeanstalk list-available-solution-stacks --region eu-west-1 --profile devenv | grep "64bit.*Linux.*running Java 8" | head -1

aws s3 cp s3://dev-ems-root s3://dev-ems-root --recursive --profile devenv

aws s3 sync . s3://dev-ems-root --profile devenv

curl -i -H "Authorization: Basic bWljcm9zZXJ2aWNlOlBhc3N3b3JkMQ==" -X POST -d 'WTF' https://configserver.qa.es.aws.net/encrypt

redo last command but as root

sudo !!

open an editor to run a command

ctrl+x+e

create a super fast ram disk

mkdir -p /mnt/ram

mount -t tmpfs tmpfs /mnt/ram -o size=8192M

don't add command to history (note the leading space)

ls -l

fix a really long command that you messed up

tunnel with ssh (local port 3337 -> remote host's 127.0.0.1 on port 6379)

ssh -L 3337:127.0.0.1:6379 root@emkc.org -N

quickly create folders

mkdir -p folder/{sub1,sub2}/{sub1,sub2,sub3}

intercept stdout and log to file

cat file | tee -a log | cat > /dev/null

exit terminal but leave all processes running

disown -a && exit

Face recognition

sudo chown -R $(whoami) /usr/local/share/man/man5 /usr/local/share/man/man7

pip3 install CMake

sudo brew install boost

brew install boost

brew update

brew unlink git

brew install git

xcode-select --install

pip3 install face_recognition

face_recognition ./knownpeople/ ./unkownpeople/ | cut -d ',' -f2

face_recognition --cpus 4 ./knownpeople/ ./unkownpeople/ | cut -d ',' -f2

sudo python -m pip install Pillow

sudo pip3 --no-cache-dir install face_recognition

sudo pip2 --no-cache-dir install face_recognition

Curl

curl -H "Origin: http://example.com" --verbose http://domain/identity/v2/healthcheck/heartbeat;contextId=abc

curl -vL --header "Content-Type: application/json" \

--request POST \

--insecure \

--data '{"name":"xyz","email":"xyz", "message":"dkfjkdf"}' \

https://dev.api.gausiaacademy.org/v1/gacontactfrmlambda/contactus

curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://hostname/resource

or posting data:

curl --data "param1=value1&param2=value2" http://hostname/resource

For file upload:

curl --form "fileupload=@filename.txt" http://hostname/resource

RESTful HTTP Post:

curl -X POST -d @filename http://hostname/resource

For logging into a site (auth):

curl -d "username=admin&password=admin&submit=Login" --dump-header headers http://localhost/Login curl -L -b headers http://localhost/

curl -v http://127.0.0.1:8080/secured/roles-allowed; echo

* Trying 127.0.0.1...

* TCP_NODELAY set

* Connected to 127.0.0.1 (127.0.0.1) port 8080 (#0)

> GET /secured/roles-allowed HTTP/1.1

> Host: 127.0.0.1:8080

> User-Agent: curl/7.54.0

> Accept: */*

< HTTP/1.1 401 Unauthorized

< Connection: keep-alive

< Content-Type: text/html;charset=UTF-8

< Content-Length: 14

< Date: Sun, 03 Mar 2019 16:32:34 GMT

* Connection #0 to host 127.0.0.1 left intact

Not authorized

Curl POST

curl -X POST "http://oauth-server/token?grant_type=client_credentials" \

-H "Accept: application/json" -H "Authorization: Basic Y2xpZW50X2lkOmNsaWVudF9zZWNyZXQ="

CURL Auth header

$ curl -H "Authorization: Bearer 60acf56d-9daf-49ba-b3be-7a423d9c7288" http://127.0.0.1:8080/secured/roles-allowed; echo

hello + client_id isSecure: false, authScheme: OAuth2

hostname -I

gets ip adderss of the machine

ls -l inf65-Message*20080410*

curl ifconfig.me

to get public ip address

ifconfig

to get local ip info

check that the process is running using

ps -ef | grep java

ps -ef | grep logging

check that the port number is active

netstat -a | grep 8080

Free Disk space in Human readable format

df -h

To see the information of only device /home file system in human readable format

df -hT /home

make request to http

curl -H "Origin: http://example.com" --verbose http://somain.com/idm/v2/healthcheck/heartbeat

Permissions

1-You can either change the permission of the directory and enable others to create files inside.

sudo chmod -R 777 /home/sixven/camp_sms/inputs

This command will change the permission of the directory recursively and enable all other users to create/modify and delete files and directories inside.

2-You can change the owner ship of this directory and make user:francisco-vergara as the owner

sudo chown -R francisco-vergara:francisco-vergara /home/sixven/camp_sms/inputs

But like this the user:sixven can't write in this folder again and thus you may moving in a circular infinite loop.

So i advise you to use Option 1.

Or if this directory will be accessed by both users you can do the following trick:

change ownership of the directory to user:francisco-vergara and keep the group owner group:sixven.

sudo chown -R francisco-vergara /home/sixven/camp_sms/inputs

Like that both users can still use the directory.

But as I said you before It's easiest and more efficient to use option 1.

Perfromance analysis

get thread Dump

ps -ef | grep java

get pid use that

kill -3 <pid>

* run top

* press Shift-H to enable Threads View

* get PID of the thread with highest CPU

* convert PID to HEX

* get stack dump of java process

* in stack dump look for thread with the matching HEX PID.

http://architects.dzone.com/articles/how-analyze-java-thread-dumps

to cut the file from line 219325 - 219327 of file inf64-MessageFactory1.std.log.20070405-0302

sed -n '219325,219327p;219327q' inf64-MessageFactory1.std.log.20070405-0302

sed -n '42192,42767p;42767q' inf64-MessageFactory1.std.log >> 1_MessageaFctory_1030-1040.log

grep -n "2007-04-16 09:37.*ThirdParty*" inf63-AuthorizationService.std.log

to set up java when install moved around

sudo update-alternatives --install “usr/bin/java” “java” “/opt/java/jdk1.7.0.21/bin/java” 1

sudo update-alternatives --set java /opt/java/jdk1.7.0_21/bin/java

Watch

watch every second free memory watch -n <secs> <command>

watch -n 1 free -m

Load test Website

will hit with 100 requests , and 10 concurrent users on the url

ab -n 100 -c 10 -g out.txt "http://someurl"

ref: https://www.inmotionhosting.com/support/edu/wordpress/performance/stress-test-with-apachebench/

Induce stress CPU to test scaling etc.

https://www.cyberciti.biz/faq/stress-test-linux-unix-server-with-stress-ng/

cat -v filename.sj to see/check format

r -ksh for last run command

history -40 will list last 40 commansds with l;ine numbers

r linenumber to run command from that line

esc + k - for back history commands

esc + j - fowd commands run list

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