Category: Computers

All things computing.

Setting up a Mac Laptop for a Software Engineer Coming from a Linux Desktop

Posted on by rchapin

I’ve recently started a new job and am setting up a MacBook Pro M4. I’ve been using either a native Linux Desktop, or a Linux Desktop as a VM on a Windows box for most of my career. There are a number things about the Mac that are different than Intel based machines running Linux following are the list of changes that I have made to make it usable as a development environment.

Disable the “Press and Hold” Feature

By → Continue reading “Setting up a Mac Laptop for a Software Engineer Coming from a Linux Desktop”

How to Install Windows 11 on a Dell Optiplex 990 (and perhaps other older hardware)

Posted on by rchapin

To perform a clean install

  1. Configure the BIOS
    • Set boot mode to UEFI
    • Set SATA configuration to AHCI
    • Enable Secure Boot/TPM
  2. Prepare a USB drive
    • Use Ventoy to create a USB drive
    • Copy the win11 ISO to the data partition of the drive
  3. Wipe the drive during the install process
    • Boot from the USB
    • When you see the “Where do you want to install Windows?” screen press Shift + F10 to open a command prompt
    • Then type the following commands,
→ Continue reading “How to Install Windows 11 on a Dell Optiplex 990 (and perhaps other older hardware)”

Mount External, Encrypted, LMV drives

Posted on by rchapin

First decrypt the drive. When I plugged it in GNOME displayed a dialog and asked for the key. I’m guessing that cryptsetup luksOpen /dev/device device_crypt would work as well.

Run lvdisplay to get the LV Path for the logical volume that you want to mount.

Then, activate the volumes , there is a way to activate a specific one volume, but the following activates them all.

vgchange -ay

Then mount it

mount <lv-path/mnt

→ Continue reading “Mount External, Encrypted, LMV drives”

PDF Commands Cheat Sheet

Posted on by rchapin

Following are a number of common PDF processing commands on a Linux box

Convert a series of images to a PDF

convert image-1 image-2 ... images.pdf

convert-im6.q16: attempt to perform an operation not allowed by the security policy `PDF’ @ error/constitute.c/IsCoderAuthorized/426.

ImageMagick, specifically version 6 (im6), is preventing the conversion of PDF files due to a security policy. To address this

  1. As root, edit /etc/ImageMagick-6/policy.xml
  2. Search for the line <policy domain="coder" rights="none" pattern="PDF" /
  3. Update rights="none" to rights="read|write"
  4. Save
→ Continue reading “PDF Commands Cheat Sheet”

Debian Package Management Cheat Sheet

Posted on by rchapin
  • List version of an installed package: dpkg -s docker-ce | grep Version
  • Show all available versions of a package: apt-cache madison <package>

Packages being held back because of phasing

Run the following command replacing the package in question

apt-get --with-new-pkgs upgrade <package-name>

The following packages have been kept back

Try the following, in order. Each is less risky than the next. Stop as soon as you have fixed the problem.

Solution 1

apt-get --with-new-pkgs upgrade <list of packages kept back>
→ Continue reading “Debian Package Management Cheat Sheet”

How to partially cherry-pick a commit in git

Posted on by rchapin

There are times when you need to cherry-pick a commit from another branch. Then there are times when you only need parts of that commit.

Following is how you can partly cherry-pick a commit to get only the changes that you need.

Get the patch for the entire commit. Include the -n for no commit so that it does not add it as a commit to your branch

git cherry-pick -n <commit>

Then unstage the the changes from the cherry-picked → Continue reading “How to partially cherry-pick a commit in git”

Go template that properly renders delimiters for a slice of structs

Posted on by rchapin

It is common to write go text/templates that range over a slice of objects to write out a list or array of items that are separated by some delimiter defined in the template.

In the case of a JSON array of objects, the cleanest output would be a , separating each object without a leading or trailing comma.

Because go template if statements are falsey in that a 0 value will evaluate to false you can write a template as → Continue reading “Go template that properly renders delimiters for a slice of structs”

Query nested arrays in PostgreSQL JSON data

Posted on by rchapin

The following is an example showing how to query multiple nested arrays in JSON data in a PostgreSQL database.

Given

CREATE TABLE sample_json (
  id serial PRIMARY KEY,
  name varchar(64),
  json_data json
);


INSERT INTO sample_json (name, json_data)
VALUES
	(
	'NA',
	'
	{
	    "location": "US",
	    "topLevelArray": [
	        {
	            "id": 1,
	            "secondLevelArray": [
	                {
	                    "key": "someKey",
	                    "operator": "=",
	                    "value": 10
	                },
	                {
	                    "key": "foo",
	                    "operator": ">=",
	                    "value": 5
	                },
	                {
	                    "key": "someOtherKey",
	                    "operator": ">",
	                    "value": 647
	                }
	            ]
	        },
	        {
	            "id":
→ Continue reading “Query nested arrays in PostgreSQL JSON data”
© 2005 Ryan Chapin