useful-commands

docker

Get all tags for a docker repository - alpine in the example

wget -q https://registry.hub.docker.com/v1/repositories/alpine/tags -O -  | sed -e 's/[][]//g' -e 's/"//g' -e 's/ //g' | tr '}' '\n'  | awk -F: '{print $3}'

Create a container with an interactive shell

docker run -it --entrypoint /bin/sh alpine:latest

kubectl

open a shell into a container in a pod with a specific label

kubectl exec -it $(kubectl get pods -l "app=my-app" -o jsonpath='{.items[0].metadata.name}') -c my-container -- /bin/sh

find/replace

Replace all occurances of a term in a git repo
Linux:

git grep -l 'original_text' | xargs sed -i 's/original_text/new_text/g'

Mac:

git grep -l 'original_text' | xargs sed -i '' -e 's/original_text/new_text/g'

MySQL

Find multi-byte characters

SELECT * FROM <table> WHERE LENGTH(col) != CHAR_LENGTH(col)

git

undo commit

git reset HEAD~

disk space

get disk usage of directories:

du -ch --max-depth=1

get disk usage summary:

df -h