Uly.me

cloud engineer

Hide All Windows Except Current

Less clutter is good. There are times when there’s too many windows in our desktop. Having less clutter leads to better focus. Here’s how to hide all Windows on a Mac OS except for the current or active one.

Command + Option + h

I wished there was a command to bring them all back, but I have not found one yet.

History Without Line Numbers

Here’s how to display history without the line numbers.

history -w /dev/stdout

Result

cd /etc/httpd/conf
view httpd.conf 
vim wiki.conf 
vim ssl.conf

CloudWatch Notifications

How to give someone access to enable/disable CloudWatch notifications.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": [
                "cloudwatch:DescribeAlarms",
                "cloudwatch:EnableAlarmActions",
                "cloudwatch:DisableAlarmActions"
            ],
            "Effect": "Allow",
            "Resource": "*"
        }
    ]
}

GCP Role Policy Binding

How to display the policy binding.

gcloud compute instances get-iam-policy SERVER --project=PROJECT_ID --zone=ZONE

Result

# There is no binding policy
etag: ACAB
 
# There is a binding policy
bindings:
- members:
  - serviceAccount:SERVICEACCOUNT
  role: organizations/xxxxxxxxxxxx/roles/ROLE
etag: xxxxxxxxxxx=
version: 1

Add a role binding policy

gcloud compute instances add-iam-policy-binding SERVER \
--project=PROJECT_ID \
--zone=ZONE \
--member=serviceAccount:SERVICEACCOUNT \
--role="organizations/xxxxxxxxxxxx/roles/ROLE"

Remove a role binding policy

gcloud compute instances remove-iam-policy-binding SERVER \
--project=PROJECT_ID \
--zone=ZONE \
--member=serviceAccount:SERVICEACCOUNT \
--role="organizations/xxxxxxxxxxxx/roles/ROLE"

Jekyll on Docker Container

Here’s how to run Jekyll in a Docker container.

mkdir blog
cd blog
docker run -v $(pwd):/site bretfisher/jekyll new .
docker run -p 4000:4000 -v $(pwd):/site bretfisher/jekyll-serve

Another option is to use docker compose. Create a docker-compose.yml file.

version: 3.5
services:
  jekyll:
    image: bretfisher/jekyll-serve
    volumes:
      - .:/site
    ports:
      - '4000:4000'

Run Jekyll.

cd blog
docker-compose up -d

Stop Jekyll.

cd blog
docker-compose down

Cleanup Stale CVS Snapshots

Here’s the script that looks mounts with stale file handles and removes them.

#!/bin/bash
file='/tmp/stale.txt'
df -h | grep Stale > $file
sed -i -e 's/df: ‘/'""'/g' $file
sed -i -e 's/’: Stale file handle/'""'/g' $file
while IFS= read -r line; do
  echo 'unmounting '$line
  umount $line
done < $file

Cleanup CVS Snapshot Volumes

How to unmount CVS snapshot volumes all at once using a Bash script. I ran into a scenario where I had to unmount 115 volumes. Instead of manually running umount on each one, I use the script below to unmount all 115 volumes. The script performs a grep for ‘.snapshot’ and then writes the results to a file. I then read the file line by line and perform unmount on each one.

#!/bin/bash
file='/tmp/snapshots.txt'
df -h | grep .snapshot | awk '{print $6}' > $file
while IFS= read -r line; do
  echo 'unmounting '$line
  umount $line
done < $file