Nov 16, 2019
Using Awk to replace only some lines —
I was trying to convert bank-issued CSV files that have a weird data layout, for automatic processing by the excellent ledger. This made me learn a new thing about awk. Follow me down the UNIXy goodness!
The data I was getting looks like this:
Transaction Date,Transaction Description,Debit Amount,Credit Amount,Balance 29/02/2018,Restaurant,14.5,,1234.2 12/03/2018,ATM withdrawal,50,,1184.2 23/04/2018,Deposited check,,100,1284.2 Note the last line having 100 in a different column: The problem is that, when receiving money, the transaction is logged in a separate entry (“Credit Amount”) than the (more common) case of debit, which goes to “Debit Amount” column.…
Oct 13, 2019
Git diff from empty commit —
In order to troubleshoot a bug in the very early history of a project using git, I needed a way to show the git diff from “nothing” to the first commit. Since git keeps a linked graph of commits, what I wanted was a diff from the commit before the first one. Searching the onlines dug up this answer on StackOverflow, showing that there’s a specific commit hash we can use to diff from “nothing” to the first commit:…
Oct 9, 2019
Reverse-engineering webapp APIs with Firefox —
I’m writing code to back up my user data off a website that lets me see all of my info (including querying by time, account etc) but doesn’t have export features (officially). I am certain there’s an API behind the site that I just have to make sense of.
Since the webapp is requesting data from the API when I click, we should be able to record the web traffic to explore the API.…
Oct 6, 2019
Git diff for prose —
When writing long sentences in documentation repositories, git tends to show really unhelpful diffs. They are unreadable because long lines aren’t broken, which hides edits happening towards end of line. A colleague of mine asked me if git couldn’t be configured to make this sort of thing more obvious. Challenge accepted!
Figure 1: Can you spot the edit made in a long line of text?
Kaushal Modi’s blog post on git diff for minified JS and CSS inspired this idea for all you prose lovers.…
Oct 6, 2019
Git pretty graph —
Get a cool graph of commits from the command line! For newbies and experts alike, git is a bit hard to visualize. Here’s a handy git command to make understanding git easier.
git log --decorate --oneline --graph Figure 1: Git graph of this repository
This can be made into a git command via an entry your ~/.gitconfig:
[alias] graph = log --decorate --oneline --graph Code Snippet 1: Alias "…
Oct 1, 2019
Presenting Android terminal with Termux (EdLug) —
Last night, I presented about Termux to EdLug, the Edinburgh Linux User group (see the event page on meetup.com) in a talk titled “The freedom of shelling out on Android”. It was tons of fun showing off how your Android phone/tablet getting a terminal unlocks a powerful tool!
I've made the slides available on this website, click on the slide below. Remember that there are speaker notes for people following at home, press `S` to use them.…
Sep 18, 2019
First post —
Welcome to my website!
This blog is meant to record some of the thoughts I keep coming back to, or discussions I’ve had over and over again with different people. My rule of thumb for inclusion here is “if you’ve had to say it more than twice, it’s time to write it down”.
See the About page for my background and motivations.
Look forward more posts as I try to condense my thoughts in written form.…