mirror of
https://gitea.com/mcereda/oam.git
synced 2026-02-09 13:44:24 +00:00
50 lines
1.8 KiB
Markdown
50 lines
1.8 KiB
Markdown
# GNU Parallel
|
|
|
|
## TL;DR
|
|
|
|
```sh
|
|
# Group output ('--group', defaults to on).
|
|
# Fill up CPU threads ('--jobs 0' or '--jobs 100%').
|
|
# Use newline as delimiter for the arguments in input.
|
|
# Simulate and print to output the command that would have been executed.
|
|
find . -type f \
|
|
| parallel --group --jobs 0 --delimiter '\n' --dry-run clamscan {}
|
|
|
|
# Rsync all folders in a directory to a NAS.
|
|
# So it one by one, and print and properly quote the command before execution.
|
|
parallel -qt -j 1 \
|
|
rsync -a --info=stats2 {} nas.lan:/shares/backup/ \
|
|
::: backup/.snapshots/*
|
|
|
|
# Get the exit status of all subjobs ('--joblog $outfile').
|
|
# Use all the threads you can (--jobs 0), hammering the CPU.
|
|
find . -type d -name .git -exec dirname "{}" + \
|
|
| parallel --jobs 0 --tagstring {/} --joblog - \
|
|
'git -C {} pull --recurse-submodules'
|
|
|
|
# Inject Istio's sidecar to all Deployments in a Namespace.
|
|
kubectl get deployments -o jsonpath='{.items[*].metadata.name}' \
|
|
| parallel --jobs 0 'kubectl -n ${NAMESPACE:-default} apply -f \
|
|
<(istioctl kube-inject -f \
|
|
<(kubectl get deployments,services {} -o json))'
|
|
|
|
# Given a list of Namespaces, get all Pods in them and the Nodes they are
|
|
# running on.
|
|
parallel --group --jobs 100% --tag \
|
|
"kubectl --context $KUBE_CONTEXT --namespace {} get pods --output json \
|
|
| jq -r '.items[] | .metadata.name + \"\t\" + .spec.nodeName' -" \
|
|
::: "${NAMESPACES}" \
|
|
| column -t
|
|
```
|
|
|
|
## Further readings
|
|
|
|
- GNU Parallel's [man page]
|
|
- GNU Parallel's [tutorial]
|
|
- [Obtaining exit status values from GNU parallel]
|
|
|
|
[man page]: https://www.gnu.org/software/parallel/man.html
|
|
[tutorial]: https://www.gnu.org/software/parallel/parallel_tutorial.html
|
|
|
|
[obtaining exit status values from gnu parallel]: https://stackoverflow.com/questions/6310181/obtaining-exit-status-values-from-gnu-parallel#6789085
|