When parsing a string that is divided by a separator char, getting the first N values OR last N values is a common scenario when dealing with: IP address separated by periods, e.g. “10.11.12.13” File path separated by forward slash “/tmp/myfolder/subpath1/subpath2/subpath3” Fully qualified domain separated by periods “sub1.sub2.my.domain.com”
The need to configure a specific pod’s container arguments is a common Kubernetes administration task. As examples, you might need to enable verbose logging, set an explicit value to override a default, or configure a host name or port set in a container’s arguments. In the example below, we are targeting the ‘metrics-server’ in the … Kubernetes: patching container arguments array with kubectl and jq
Below is an example using ‘kubectl patch’ to update the securityContext of a single, specific container named ‘my-init-container1’ of the ‘initContainers’ list. kubectl patch deployment my-deployment -n default –patch='{ “spec”: { “template”: { “spec”: { “initContainers”: [ { “name”: “my-init-container1”, “securityContext”: { “runAsUser”: 999 } } ] } } } }’ But ‘initContainers’ is an … Kubernetes: patch every array element using kubectl and jq
Whether looking at differences in filenames, installed packages, etc. it can be useful to calculate the difference between two Bash arrays. SiegeX on stackoverflow.com offered the following function using awk, and I have built a full example available on github. function arraydiff() { awk ‘BEGIN{RS=ORS=” “} {NR==FNR?a[$0]++:a[$0]–} END{for(k in a)if(a[k])print k}’ <(echo -n “${!1}”) <(echo … Bash: Difference between two arrays
Just as in other programming languages, associative arrays in Bash are useful for search, set management, and keying into a list of values. The label may be different, but whether called “map”, “dictionary”, or “associative array”, the same concepts apply. In its simplest form, here is an initialization and then loop through the key/value pairs. … Bash: Associative array initialization and usage