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Linux Commands




Network

Wget

wget is a http client

wget http://digitalvellum.next.xxxx-labs.com/ping

Curl

Make a web request
curl -v ppe.courseadmin.he.pearsoncmg.com/console/launch?courseId=y

File Upload
curl -v -u username:password --upload-file he-mypearson-parent-3.6.pom https://devops-tools.xxxx.com/nexus-deps/service/local/repositories/Releases/content/com/ltg/3.6-SNAPSHOT/he-myson-parent-3.6.pom

nc

Ping to a port
nc -zv 10.20.238.210 1521

Netstat


Show all network connections

netstat


netstat -cnulp

netstat -a -n | grep "LIST"

Get number of connections

netstat --tcp | wc -l

Get ports with pid

netstat -lnptu

Route

route -n

Telnet

telnet 10.52.208.59
telnet 10.52.208.59 9080


network trace

mtr 10.32.149.159

Server ………….


Get shared server info
df -h

#number of cores
nproc

# CPU architecture information
lscpu

#restart ubunutu
sudo reboot

#linux os version
uname -a

cat /etc/*-release

creating a link
ln -sf /usr/lib/firefox/firefox /usr/bin/firefox


#show all env variables sorted
env | sort

sort
ll -t
 

process

linux you can find the application pid by using
>> netstat -tulpn

process details
ps -ef | grep 4377

show running processors
ps -ef

kill process id 3071
kill -9 3071
>>kill whatever process using 61521 port
      lsof -ti:61521 | xargs kill -9

##kill process
pkill -f vmstat
pkill -f pidstat

Permissions


change ownership of a folder and sub
chown -R aravinda:aravinda eclipse_sts

change file permission
chmod ugo+rwx file4

#change chmod
chmod o-rw myfile

Compression


ZIP

tar -zcvf compressFileName.tar.gz folderToCompress

#extract to destination_folder
tar -xvzf env.tar.gz -C destination_folder

unzip compressFileName.zip -d folderToCompress

#unzip
tar xvzf bos03-prod-env.tar.gz

#view only
vim xxx.tar.gz

#open file
press enter on line of the file to open

#search a file in jar
                find *.jar | xargs grep className.class


Copy

scp -- ssh copy

scp courseDetails.min.js portweb@10.52.129.12:/install/tomcat/webapps/media/javascript

ENVIRONMENT VARIABLES

SET ENVIRONMENT VARIABLES
vi /etc/environment
>> JAVA_HOME="/usr/lib/jvm/open-jdk"
source /etc/environment

#set java per session
export PATH=$PATH:/export/home/apps/jdk1.7.0_51/bin
--get java location by >>ps -ef

#show env variables
env


vi editor

show line numbers
>> :set nu

Edit File

scripts to edit file in linux

#replace 8443 with 8080
sed -i.bak 's/8443/8080/g' server.xml

#add code after using the shared thread pool'
sed -i.bak '/using the shared thread pool/r ssh_properties.txt' server.xml

DISK SPACE


#list free disk space:
df -h

#which sub-folders spend how much disk space
du -h --max-depth=1

#top 10 largest file/directories:
du -a /var | sort -n -r | head -n 10

#memory usage per process
ps -aux


iptables


//GET request for "http://cert.coursemgmt.he.xxxx.com/course/epa38191":Connection reset
//java.net.SocketException: Connection reset

#from source - should connect to the source
telnet 10.52.208.59 9080

#from destination, reset ports
iptables -F

iptables -nL

memory


#free memory > buffers/cache
free -m
#processors using resources
top

Cron Tab


#cron logs
grep CRON /var/log/syslog

Disable the cronjob.
30 3 * * * bash /export/home/portal/sync_portal_enrollments.sh

SSH Tunneling

ssh -f -L 61521:dbs-b3-0301:1521 usenanu@bridge.xxxx.com -N

SSH


ssh portaltest01

Nohup


nohup /export/home/portal/shared/app/jdk1.7.0_45/bin/java -jar /machineagent.jar &

service

#staring course managemtn simulator
    cd /etc
    sudo service httpd start

memcache

#memcache restart
pkill -f memcached

nohup /export/home/apps/memcached-1.4.15/bin/memcached -v -m 1024 -p 11211 -u portweb -l $HOSTNAME > /dev/null &


or

sudo /etc/init.d/memcached start

#check memchached status
 netstat -tulpn | grep 11211

  ps -e | grep memcached

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