Undo Commits

Commited but not pushed to the remote?

git reset --soft HEAD^

Commit pushed to the remote?

git reset HEAD^ --hard
$ git push origin -f

Resizing Partition on UBUNTU

SOURCE: 

https://askubuntu.com/questions/116351/increase-partition-size-on-which-ubuntu-is-installed/116367 

As a matter of fact, you CAN enlarge the root filesystem while Ubuntu is running (I learned this recently myself here) - this sounds incredible but it's true :)
Here's the list of steps for a simple scenario where you have two partitions, /dev/sda1 is an ext4 partition the OS is booted from and /dev/sdb2 is swap. For this exercise we want to remove the swap partition an extend /dev/sda1 to the whole disk.
As always, make sure you have a backup of your data - since we're going to modify the partition table there's a chance to lose all your data if you make a typo, for example.
Run sudo fdisk /dev/sda

• use p to list the partitions. Make note of the start cylinder of /dev/sda1

• use d to delete first the swap partition (2) and then the /dev/sda1 partition. This is very scary but is actually harmless as the data is not written to the disk until you write the changes to the disk.

• use n to create a new primary partition. Make sure its start cylinder is exactly the same as the old /dev/sda1 used to have. For the end cylinder agree with the default choice, which is to make the partition to span the whole disk.

• use a to toggle the bootable flag on the new /dev/sda1

• review your changes, make a deep breath and use w to write the new partition table to disk. You'll get a message telling that the kernel couldn't re-read the partition table because the device is busy, but that's ok.

Reboot with sudo reboot. When the system boots, you'll have a smaller filesystem living inside a larger partition.
The next magic command is resize2fs. Run sudo resize2fs /dev/sda1 - this form will default to making the filesystem to take all available space on the partition.
That's it, we've just resized a partition on which Ubuntu is installed, without booting from an external drive.

Moving from Jenkins (Tomcat) to Jenkins Standalone [UBUNTU]

SSH into ubuntu
sudo apt-get update
sudo apt-get install jenkins
sudo service jenkins stop
cd /var/lib/jenkins
rm -rf ./*
cp -a /var/lib/tomcat8/webapps/jenkins .
chown -R jenkins .
chgrp -R jenkins .
sudo service jenkins start

Jenkins Webhook, Only build Specific Branch after receiving web hook. e.g. only build master

With a web hook a request is made regardless of which branch it is on. Initially this would cause my Jenkins to initiate a build (on master) even when the commit was pushed to develop. To fix this we can follow these steps:

• Open your jenkins project
• configure it to use: Poll SCM (but leave the schedule blank)
• save and exit

in Bitbucket / Github create a web hook and enter the following url (replacing your jenkins & git project details)

http://<your domain>/jenkins/git/notifyCommit?url=<your git repository url>

eg

http://fakewebsite.com:8080/jenkins/git/notifyCommit?url=git@bitbucket.org:faceuser/fakeproject.git

This will do the following:

1. Send a web hook request to your jenkins
2. Jenkins will process this request and look for Jenkins projects using the specified gitproject (e.g. git@bitbucket.org:faceuser/fakeproject.git)
3. Jenkins will then poll git looking for changes on the specified branch

Jenkins unable to post to twitter due to Twitter-plugin not using SSL

Same problem as this
https://issues.jenkins-ci.org/browse/JENKINS-25740

 but the solution was to also replace jar the following files under
$jenkinsdir/plugins/twitter/WEB-INF/lib

twitter4j-core-3.0.3.jar with twitter4j-core-3.0.5.jar
twitter4j-async-3.0.3.jar with twitter4j-async-3.0.5.jar

Download from
http://central.maven.org/maven2/org/twitter4j/twitter4j-core/3.0.5/

reload jenkins deployment in tomcat manager and voila! it works!

Jenkins job cannot create dirs under /home/jenkins/.m2/

ssh to the machine and check who ones the files/dirs if it owned by root change it to the tomcat users

sudo chown -R username:group directory




Python Extracting 9 digit number from tomcat access log files into a unique set and printing to the screen

I had to extract all the 9 digit IDs that were used in a tomcat access log. Here is how I solved it with Python

import re
import os

from collections import Counter
# Compile the regular expressions \d{9} selects numbers that are 9 digits longs
p = re.compile('\d{9}', re.IGNORECASE)
output_file_name = 'output.csv'
# Initiate an array to store the students ids in
most_active = []
#for the files in this directory
for name in os.listdir("."):
    #if it starts with localhost_access_log & ends with a .txt extension
    if name.startswith("localhost_access_log") and name.endswith(".txt"):
        #read its contents
        with open(name, 'r') as myfile:
            print("Reading file: "+name)
            data=myfile.read().replace('\n', '')
            #Add the regex matches to the array
            most_active = most_active + re.findall(p, data)
# Count how many times a student id is repeated in the list
# This will tell us the most active students in the app
count = Counter(most_active)

# For each of the students, order them from most common to least
output_file = open(output_file_name,"w")
output_file.write("Student ID, Activity\n")
for student in count.most_common():
    line = str(student[0])+","+str(student[1])
    #print(line)
    
    output_file.write(line+"\n")
output_file.close()
print("File written successfully: "+output_file_name)
#Print out the total amount of students
print("Total Students:"+ str(len(count)))