Technology

Technology - Volunteering

Coolest Projects Ireland: Reflections of a Proud Mentor and Parent

March 15, 2025 by

My son and I recently attended the Coolest Projects technology showcase in Dublin, Ireland and had a simply wonderful day, so I thought I’d share some reflections of the event, both as a parent and as a mentor at my local Code Club in Tramore, Co. Waterford.

Tramore Code Club

Founded in 2014, Tramore Code Club (formerly known as CoderDojo, Tramore) is a volunteer-led group that provides opportunities for young children to explore the world of computer programming in a relaxed and friendly environment that is rooted in the spirit of exploration through collaboration.

The club is completely free and runs for two hours each Saturday, from 4pm – 6pm.

Code Club (via the Raspberry Pi Foundation)

Code Club is a voluntary initiative that aims to provide opportunities for children aged 9 to 13 to develop coding skills through free after-school clubs. Their aim is to help young people to develop the skills, knowledge, and mindsets to enable them to thrive in a world that is increasingly shaped by digital technologies. More than 2 million young people are involved in code clubs in 100+ countries worldwide [Source: CodeClub.org, Wikipedia]

The Code Club initiative is a part of the Raspberry Pi Foundation, an educational charity with a global mission to help young people realise their full potential through the power of computing and digital technologies [Source: RaspberrryPi.org]

Coolest Projects

Coolest Projects is an annual, in-person technology showcase event (with an online option also available) that provides a forum for young people to showcase their digital creations and skills.

The event has been taking place in-person in Dublin, Ireland for more than 10 years and has gone from strength to strength during that time, with hundreds of families travelling from across the country to take part each year, showcasing their ideas in a friendly and supportive environment.

Bobby’s Ukulele Trainer

My son and I were delighted to attend the Coolest Projects in-person event in 2025 (which took place at the Sport Ireland National Indoor Arena in Dublin) as part of a large delegation from Tramore Code Club, where he showcased Bobby’s Ukulele Trainer project.

Written in Scratch and inspired by a project created by his sister 9 years earlier (as well as his schoolteacher who introduced him to the Ukulele), his project helps people learn to play the Ukulele by showing them where to place their fingers for a selection of popular chords. 

His project also plays samples of each chord (recorded by him) so you can hear how you’re doing, and it supports both right-handed and left-handed players so is more accessible to all.

We were blown away by how popular this project was on the day, with large groups of children and adults (including other mentors and volunteers) calling by his stand to try their hand at playing the Ukulele which we had brought along for the day.

We were even treated to a visit by Raspberry Pi Foundation CEO, Philip Colligan, who stopped by to try his hand at some impromptu Ukulele lessons, also leaving with a big smile on his face.

A Mentor’s Perspective

So, what was Coolest Projects, Ireland like as a mentor (from Tramore Code Club)?

The 2025 event featured projects in thematic areas including Scratch, Gaming, Web Development, Hardware and AI. There were plenty of volunteers on hand to ensure everyone was made to feel welcome and each child was provided with a packed lunch after the main showcase sessions.

There were lots of other mentors and parents on hand, too, who took time to visit many of the projects on display, offering support, guidance and encouragement to the children, which was very much appreciated.

The volunteers on the day were incredibly welcoming from the moment we walked through the doors, and went out of their way to ensure the children were given every opportunity to showcase their projects to as many people as possible. 

The variety of activities available to the attendees, the quality of the broadband, and the selection of projects coupled with the friendliness of the volunteers were particular highlights for our family.

A Parent’s Perspective

In terms of my impression of the event as a parent, I felt immensely proud of how my child interacted freely with other children, parents, mentors and volunteers alike. This enhanced their communication skills and gave them invaluable experience about how to explain technical and musical concepts to non-technical and non-musical people of all ages and abilities.

There was a noticeable mixture of interests and abilities among the wide variety of visitors to our child’s project stand, each of whom were clearly very at home at the event. It was clear to me that significant consideration had been given to make sure everyone felt included at the event. We certainly did!

Your child will have a brilliant day and will be respected, included and celebrated in a safe, active and fun environment from the moment they walk through the door. Parents who feel less technical themselves need not worry about this. There’s plenty to enjoy for everyone and anyone. 

All in all, my child thoroughly enjoyed the event and has been telling everyone about it since attending. They’ve already asked about returning again next year.

FeedHenry - Humour - Technology

How Santa Sleighed our Backend

December 23, 2021 by

Like anyone that has worked in the IT industry for as long as I have, I’ve encountered my fair share of horror stories (or learning opportunities, as we later learned to call them), where technology lets you down or behaves in completely unforeseen ways, with highly stressful consequences.

One of my all-time favourite examples of this (although it didn’t feel like it at the time) involved Santa Claus, of all people, and having told the story in person so many times, I finally found the time to write it down (just in time for Christmas) in all its glorious detail.

Full credit goes to Evan Shortiss and Philip Hayes (who lived through this with us) for helping to tell the story in this format, with Evan devising the article title and Philip providing the technical accuracy to back it up. So here goes…

A Christmas Tale

It was 23 December 2011 and the hardworking staff at our startup company, which was punching above its weight in the mobile applications and cloud space at the time, were on the wind down to a well deserved Christmas break after a very busy and successful year.

‘Twas two nights before Christmas, when all through the house, not an engineer was stirring, not even their mouse…

As their Cloud Operations team had done their due diligence and introduced a platform change freeze the week before (notifying customers accordingly and finalising a support crew that could assist if any issues arose during the holidays, which rarely happened anyway), most of the staff has already started their holidays in the days before, so the office was pretty calm and quiet.

One of our larger profile customers at the time ran the local national airport and were using a custom solution powered by our platform to provide flight information and other services to airport customers. Their solution comprised a publicly available, cross-platform mobile app with a cloud-based, Node.js backend that integrated with some of their own backend systems, parsing data that was delivered via a message queue and storing it in a local cache.

Then, suddenly, the phone rang…

Panic Stations

The customer’s mobile app had just stopped working on the busiest day of the year, leaving thousands of passengers virtually stranded, with no up-to-date flight information. Nothing had changed, though; we were in a change freeze and this same application had been operating flawlessly for months, processing hundreds of thousands of messages without issue. This was quickly verified by the dutiful support crew who confirmed that no changes had been made to the front-end or back-end of the application, and yet the mobile app continued to fail.

In the hours that followed, long into the evening that was, almost every engineer in the company was summoned back from holidays to help get to the root cause of this issue, with stress levels on the increase and patience declining fast. There was also no sign of anyone that looked even remotely like Hans Gruber to blame for the drama that ensued 🙂

Some time later, one of the engineers discovered (via some system logs) that some of the code responsible for parsing messages from the customer’s backend systems was throwing errors. Specifically, the code that mapped airline (ICAO) codes to human readable airline names had a hardcoded table with predefined entries, supporting only the entries in that table and generating errors for anything else it encountered.

Having verified that there was, in fact, decent error handling in place for the code segment in question, this still did not explain why the backend application was still crashing continuously. A few more hours passed and attention turned to the actual data being sent by the customer’s messaging system. It was not the only remaining variable in the entire equation at hand.

Learning Opportunities

And then, suddenly, there it was, staring us in our (now very red) faces. Santa was on his way!

It turns out that, through their inner child and the goodness of their hearts, and in keeping with what had become an annual tradition, the airport IT staff had injected a fake flight (by Santa Airlines) into the arrivals messaging queue. However, the associated airline code (SAN) was not in the table of predefined entries in the backend application, so was generating an error.

However, cruelly, it then transpired that while the error was being caught and handled, there was a small bug in the error handling routine which was preventing the application from processing subsequent messages, ultimately causing it to crash, over and over again. 

So, in the end, the addition of a fake flight to bring some festive cheer to airport customers and their families exposed a hidden bug in our application, which “sleighed” our backend!

Lessons Learned

No matter how reliable you believe your data is, or how long your application has been running without issue, edge cases will still happen. A simple unit test would have caught the bug described above and prevented this high profile system from failing at one of the busiest times of the year, causing enormous amounts of stress to everyone involved.

Aerogear - Cloud - General - Red Hat - Technology

Building a Cloud while in the Clouds

July 18, 2018 by

So you’re heading to the US for some business meetings with your Chief Architect then you get upgraded to business class where there’s free WiFi and you’ve got 6 hours to kill. You options are watch movies (seen them all before), drink wine (a given) and/or have an in-flight hackathon to test out the quality of the WiFi.

And so we did just that and went ahead and provisioned an instance of the latest Aerogear Mobile Services powered by OpenShift Origin, resulting in very own cloud platform built in the clouds!

Indeed, the Internet connection was spotty at best but in between the spottiness, our installer script did run to completion…

…and we did (eventually) get the all-elusive OpenShift Console with the Mobile tab in all it’s beautiful glory.

We also needed to get very creative in order to share the screen shots (which involved USB-C cables and several other travel accessories that only an Architect and Director would have) despite physically sitting beside each other, but such is life. And for good measure, we also published this blog article from the air!

So what have you done to test your in-flight WiFi and how was it for you?

Photography - Technology

A case for more Open Source at Apple

April 17, 2017 by

Open Source Context

I’ve been involved in the software industry for almost 30 years and have long been an admirer of open source software, both in terms of what it stands for and in terms of the inherent value it provides to the communities that create it and support it.

I’m even old enough to remember reading about the creation of the Free Software Foundation itself by Richard Stallman in 1985 and couldn’t be happier to now find myself working at the king pins of open source, Red Hat (through the acquisition of FeedHenry in 2014).

And while in recent years it’s been reassuring to see more and more other companies adopt an open source strategy for some of their products, including the likes of Apple and Microsoft, it’s been equally soul destroying having to live with the continued closed source nature of some of their other products. Take Apple’s Photos app for iOS as a case in point.

Apple iPhoto

Some time around 2011, I took the decision to switch to Apple’s excellent iPhoto app for managing my personal photo collection, principally due the facial recognition and geolocation features but also because of the exceptional and seamless user experience across the multitude of Apple devices I was amassing.

Then, in late 2012, I undertook a very lengthly personal project (spanning 9 months or more) to convert my extended family’s vintage photo collection to digital format, importing them to iPhoto and going the extra mile to complete the facial and location tagging also.

The resultant experience was incredible, particularly when synced onto my iPad of the time (running iOS 6). Hours at a time were spent perusing through the memories it invoked, with brief interludes of tears and laughter along the way. What was particularly astonishing was how the older generations embraced the iPad experience within minutes of holding the device for the very first time. This was the very essence of what Steve Jobs worked his entire life for, and for this I am eternally grateful to the genius he clearly was.

Apple Photos

However, since then, with the launch of subsequent releases of iOS I have never been able to recreate the same experience, for two reasons.

Firstly, the user interface of the iPhoto app kept changing (becoming less intuitive each time, proven by the lessening magic experienced by the same generation that previously loved it so much), and secondly, it was replaced by the Photos app outright which, incredibly, has one simple but quite incredulous bug – it cannot sort!

Yes, quite incredibly, the Photos app for iOS cannot sort my photos when using the Faces view. If you don’t believe me, just Google phrase “apple photos app sort faces” and take your pick of the articles lamenting such a rudimentary failing.

A Case for Open Source

“So what does this have to with open source?“, I hear you ask.

Well, trawling through the countless support articles on Apple’s user forums, it seems that this bug has been confirmed by hundreds of users but, several years later, it is still not fixed. If this was an open source project, it would have been long since fixed by any one of a number of members of the community I’m sure would form around it, and potentially even by me!

So c’mon Apple, let’s have some more open source and let’s make your products better, together.

General - Red Hat - Technology

A Simple Model for Managing Change Windows

February 16, 2017 by

One of the more common things we do in the Cloud Operations team at Red Hat Mobile is facilitate changes to environments hosted on the Red Hat Mobile Application Platform, either on behalf of our customers or for our own internal operational purposes.

These are normally done within what is commonly known as a “Change Window”, which is a predetermined period of time during which specific changes are allowed to be made to a system, in the knowledge that fewer people will be using the system or where some level of service impact (or diminished performance) has been deemed acceptable by the business owner.

We have used a number of different models for managing Change Windows over the years, but one of our favourite approaches (that adapts equally well to both simple and complex changes and that is easy for our customers and internal stakeholders to understand) is this 5-phase model.

Planning

The planning phase is basically about identifying (and documenting) a solid plan that will serve as a rule book for all the other elements in this model (below). In addition to specifying the (technical) steps required to make (and validate) the necessary changes, your plan should also include additional (non-technical) information that you will most likely need to share externally so as to set the appropriate expectations with the affected users. This includes specifying:

  • What changes are you planning to make?
  • When are you proposing to make them?
  • How long will they take to complete?
  • What will the impact (if any) be on the users of the system before, during and after the changes are made?
  • Is there anything your customers/users need to do beforehand or afterwards?
  • Why are you making these changes?

Your planning phase should also include a provision for formally communicating the key elements of your plan (above) with those interested in (or affected by) it.

Commencement

The commencement phase is about executing on the elements of your plan that can be done ahead of time (i.e. in the hours or minutes before the Change Window formally opens) but that do not involve any actual changes.

Examples include:

  1. Capturing the current state of the system (before it is changed) so that you can verify the system has returned to this state afterwards.
  2. Issuing a final communication notice to your users, confirming that the Change Window is still going ahead.
  3. Configuring any monitoring dashboards so that the progress (and impact) of the changes can be analysed in real time once they commence.

The commencement phase can be a very effective way to maximise the time available during the formal Change Window itself, giving you extra time to test your changes or handle any unexpected issues that arise.

Execution

The execution phase is where the planned changes actually take place. Ideally, this will involve iterating through a predefined set of commands (or steps) in accordance with your plan.

One important mantra which has stood us in good stead here over the years is, “stick to the plan”. By this we mean, within reason, try not to get distracted by minor variations in system responses which could consume valuable time, to the point where you run out of time and have to abandon (or roll back) your changes.

It’s also strongly recommended that the input to (and outputs from) all commands/steps are recorded for reference. This data can be invaluable later on if there is a delayed impact on the system and steps need to be retraced.

Validation

Again this phase should be about iterating through a predefined set of verification steps that may include examining various monitoring dashboards, running automated acceptance/regression test tooling, all in accordance with two very basic principles:

  1. Have the changes achieved what they were designed to (i.e. does the new functionality work)?
  2. Have there been any unintended consequences of the changes (i.e. does all the old functionality still work, or have you broken something)?

Again, it’s very important to capture evidence of the outcomes from validation phase, both as evidence to confirm the changes have been completed successfully and that the system has returned to it’s original state.

All Clear

This phase is very closely linked to the validation phase but is slightly more abstract (and usually less technical) in nature. It’s primary purpose is to act as a higher-level checklist of tasks that must to be completed, in order that the final, formal communication to the customer (or users) can be sent, confirming that the work has been completed and verified successfully.

 

Amazon Web Services - Technology

How to exhaust the processing power of 128 CPUs

October 26, 2016 by

Amazon Web Services launched another first earlier this year in the form of a virtual server (or EC2 instance as they call it) with a staggering 128 virtual CPUs and over 1.9 Terabytes of memory.

The instance, which is an x1.32xlarge in their naming scheme, could cost you as much as $115,000 per year to operate but you could certainly reduce that figure significantly (e.g. $79,000) if you knew ahead of time that you would be running it 24×7 during that time.

In any case, during a recent experiment using one of these instances, we set about trying to find some novel ways to max out the processing power and memory, and here are the two techniques we settled on (with evidence of each of them in action).

CPU Exhaustion

This was strangely a lot easier than we expected and simply involved using the Unix yes command which, it seems, draws excessive amounts of processing power when used in isolation from it’s normal purpose.

So for our x1.32xlarge instance, with it’s 128 vCPUs, we used the command below to spawn 127 processes each running the yes command and we then monitored it’s impact using the htop command.

$ for i in {1..127}; do yes>/dev/null & done

And here it is in action:

The reason for spawning just 127 processes (instead of the full 128) was to ensure that the htop monitoring utility itself would have enough resources to be able to function, which can been seen clearly above.

Memory Exhaustion

Exhausting the memory was a little harder (to do quickly) but one of the more hard-core Unix guys came up with this old-school beauty which combines the processor-hungry yes command with some complex character replacements, plus searches for character sequences that will never be found.

$ for i in `seq 1 40`; do cat <(yes | tr \\n x | head -c $((10240*1024*4096))) <(sleep 18000) | grep n &  done

And here it is in action too, noting the actual memory usage in the bottom, left:

Note also that the CPU usage, while almost at the limit, is not as clear-cut as before and all processors are being utilised equally (for the most part). Note also the Load Average of 235 (bottom, right of centre) which supports the theory that Unix systems can theoretically sustain load averages of twice the number of processors before encountering performance issues. Some folks believe this to be closed to one times the number of processors but the results above suggest otherwise.

Amazon Web Services X1

The original announcement of the X1 instance type is available at:

Security - Technology

Monitoring the Health of your Security Certificates

January 10, 2016 by

Security Certificates

Most modern websites are protected by some form of Security Certificate that ensures the data transmitted from your computer to it (and vice versa) is encrypted. You can usually tell if you are interacting with an encrypted website via the presence of a padlock symbol (usually green in colour) near the website address in your browser.

These certificates are more commonly known as SSL Certificates but in actual fact, the more technically correct name for them is TLS Certificates (it’s just that nobody really calls them that as the older name has quite a sticky sound/feel to it).

Certificate Monitoring

In any case, one of the things we do a lot of at Red Hat Mobile is monitoring, and over the years we’ve designed a large collection of security certificate monitoring checks. The majority of these are powered by the OpenSSL command-line utility (on a Linux system), which contains some pretty neat features.

This article explains some of my favourite things you can do with this utility, targeting a website secured with an SSL Certificate.

Certificate Analysis

Certificate Dumps

Quite often, in order to extract interesting data from a security certificate you first need to dump it’s contents to a file (for subsequent analysis):

$ echo "" | openssl s_client -connect <server-address>:<port> > /tmp/cert.txt

You will, of course, need to replace <server-address> and <port> with the details of the particular website you are targeting.

Determine Expiry Date

Using the dump of your certificate from above, you can then extract it’s expiry date like this:

$ openssl x509 -in /tmp/cert.txt -noout -enddate|cut -d"=" -f2

Determine Common Name (Subject)

The Common Name (sometimes called Subject) for a security certificate is the website address by which the secured website is normally accessed. The reason it is important is that, in order for your website to operate securely (and seamlessly to the user), the Common Name in the certificate must match the server’s Internet address.

$ openssl x509 -in /tmp/cert.txt -noout -subject | sed -n '/^subject/s/^.*CN=//p' | cut -d"." -f2-

Extract Cipher List

This is a slightly more technical task but useful in some circumstances nevertheless (e.g. when determining the level or encryption being used).

$ echo "" | openssl s_client -connect <server-address>:<port> -cipher

View Certificate Chain

In order that certain security certificates can be verified more thoroughly, a trust relationship between them and the Certificate Authority (CA) that created them must be established. Most desktop web browsers are able to do this automatically (as they are pre-programmed with a list of authorities they will always trust) but some mobile devices need some assistance with establishing this trust relationship.

To assist such devices with this, the website administrator can opt to install an additional set of certificates on the server (sometimes known as Intermediate Certs) which will provide a link (or chain) from the server to the CA. This chain can be verified as follows:

$ echo "" | openssl s_client -connect <server-address>:<port> -showcerts -status -verify 0 2>&1 | egrep "Verify return|subject=/serial"

The existence of the string “0 (ok)” in the response indicates a valid certificate chain.

OpenSSL

You can find out more about the openssl command-line utility at http://manpages.ubuntu.com/manpages/xenial/en/man1/openssl.1ssl.html.

Technology - Travel

The True Value of a Modern Smartphone

August 28, 2015 by

While vacationing with my family recently, I stumbled into a conversation with my 11-year old daughter about smartphones and the ever growing number of other devices they are replacing as they digitally transform our lives.

For fun, we decided to compare the relative cost of the vacation with and without my smartphone at the time (a Samsung Galaxy S3, by the way) and by imagining if we’d taken the same vacation a mere 10 years earlier, how much extra would that vacation have cost without the same smartphone?

Smart Cost Savings

I was actually quite shocked at the outcome, both in terms of the number of other devices the modern smartphone now replaces (we managed to count 10) and at the potential cost savings it can yield, which we estimated at a whopping $3,450!

Smart Cost Analysis

The estimations below are really just for fun and are not based on very extensive research on my part (more of a gut feeling about a moment in time, plus some quick Googling). You can also assume a 3-week vacation near some theme parks in North America.

Telephony: $100

Assuming two 15 minute phone calls per week, from USA to Ireland, at mid-week peak rates, you could comfortably burn $100 here.

Camera: $1,000

Snapping around 1,000 old-school, non-digital photos (at 25 photos per 35mm roll of film) would require approximately 40 rolls of film (remember, no live preview). Then factoring in the cost of a decent SLR camera, plus plus the cost of developing those 40 rolls of film, you could comfortably spend well in excess of $1,000 here.

Of course digital cameras would indeed have been an option 10 years ago too but it’s unreasonable to suggest that a decent digital camera (with optical zoom, of sufficient portability and quality for a 3-week family vacation) could also have set you back $1,000.

Music Player: $300

The cost of an Apple iPod in 2005 was around $299.

GPS / Satellite Navigation: $400

It’s possible that in 2005, the only way to obtain a GPS system for use in North America was to rent one from the car rental company. Today, this costs around $10 per day, so let’s assume it would have cost around/under $20 in 2005.

Games Console: $300

The retail price for a Nintendo DS in 2005 was $149.99 but you also need to add in the cost of a selection of games, which cost around $50 each. Let’s be reasonable and suggest 3 games (one for each week of the vacation).

Laptop Computer: $1,000

I’m not entirely sure how practical/easy it would have been to access the Internet (at the same frequency) while on vacation in 2005 (i.e. how many outlets offered WiFi at all, never mind free WiFi). Internet Café’s would have been an option too, but would not have offered the levels of flexibility I’d had needed to catch up on emails and update/author some important business documents, so let’s assume the price of a small laptop here.

Mobile Hotspot / MiFi: $200

Again, not quite sure if these were freely available (or feasible) in 2005, but let’s nominally assume they were and price them at double what they cost today, plus $100 for Internet access itself

Alarm Clock: $50

I guess you could request a wake up call in your hotel but if you were not staying in a hotel and needed an alarm clock, you’d either have needed a watch with one on it, or had to purchase an alarm clock.

Compass: $50

Entirely optional of course, but if you’re the outdoor type and fancy a little roaming in some of the national parks, you might like to have a decent compass with you.

Torch: $50

Again, if you’re the outdoor type, or just like to have some basic/emergency tools with you on vacation, you might have brought (or purchased) a portable torch or Maglite Flashlight.

Scripting - Technology

10 Ways to Analyzing your Apache Access Logs using Bash

January 6, 2015 by

Since it’s original launch in 1995, the Apache Web Server continues to be one of the most popular web servers in use today. One of my favourite parts of working with Apache during this time has been discovering and analysing the wealth of valuable information contains its access logs (i.e. the files produced on foot of general usage from users viewing the websites served by Apache on a given server).

And while there are plenty of free tools available to help analyse and visualise this information (in an automated or report-driven way), it can often be quicker (and more efficient) to just get down and dirty with the raw logs and fetch the data you need that way instead (subject to traffic volumes and log file sizes, of course). This is also a lot more fun.

For the purposes of this discussion, let’s assume that you are working with compressed backups of the access logs and have a single, compressed file for each day of the month (e.g. the logs were rotated by the operating system). I’m also assuming that you are using the standard “combined” LogFormat.

1. Total Number of Requests

This is just a simple word count (wc) on the relevant file(s):

Requests For Single Day

$ zcat access.log-2014-12-31.gz | wc -l

Requests For Entire Month

$ zcat access.log-2014-12-*.gz | wc -l

2. Requests per Day (or Month)

This will show the number of requests per day for a given month:

$ for d in {01..31}; do echo "$d = `zcat access.log-2014-12-$d.gz | wc -l`"; done

Or the requests per month for a given year:

$ for m in {01..12}; do echo "$m = `zcat access.log-2014-$m-*.gz | wc -l`"; done

3. Traffic Sources

Show the list of unique IP addresses the given requests orginated from:

$ zcat access.log-2014-12-31.gz | cut -d" " -f1 | sort | uniq

List the unique IP addresses along with the number of requests from each, from lowest to highest:

$ zcat access.log-2014-12-31.gz | cut -d" " -f1 | sort | uniq -c | sort -n

4. Traffic Volumes

Show the number of requests per minute over a given day:

$ zcat access.log-2014-12-31.gz | cut -d" " -f4 | cut -d":" -f2,3 | uniq -c

Show the number of requests per second over a given day:

$ zcat access.log-2014-12-31.gz | cut -d" " -f4 | cut -d":" -f2,3,4 | uniq -c

5. Traffic Peaks

Show the peak number of requests per minute for a given day:

$ zcat access.log-2014-12-31.gz | cut -d" " -f4 | cut -d":" -f2,3 | uniq -c | sort -n

Show the peak number of requests per second for a given day:

$ zcat access.log-2014-12-31.gz | cut -d" " -f4 | cut -d":" -f2,3,4 | uniq -c | sort -n

Commands Reference

The selection of Unix commands used to conduct the above analysis (along with what they’re doing above) was:

  • zcat – prints the contents of a compressed file.
  • wc – counts the number of lines in a file (or input stream)
  • cut – splits data based on a delimiting character.
  • sort – sorts data, either alphabetically or numerically (via -n option).
  • uniq – removes duplicates from a list, or shows how much duplication there is.