# Using Cloud CLI

> Cloud CLI patterns for GCP and AWS. Use when running bq queries, gcloud commands, aws commands, or making decisions about cloud services. Covers BigQuery cost optimization and operational best practices.

- Skill: `julianobarbosa/using-cloud-cli` (Agent Skill, multi-file: 4 files)
- Install (CLI): `npx skillmds@latest add julianobarbosa/using-cloud-cli`
- Raw SKILL.md: https://api.skillmd.com/api/skills/julianobarbosa/using-cloud-cli/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- Author: julianobarbosa (https://skillmd.com/u/julianobarbosa)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/julianobarbosa/using-cloud-cli

---


# Cloud CLI Patterns

Credentials are pre-configured. Use `--help` or Context7 for syntax.

## BigQuery

```bash
# Always estimate cost first
bq query --dry_run --use_legacy_sql=false 'SELECT ...'

# Run query
bq query --use_legacy_sql=false --format=json 'SELECT ...'

# List tables
bq ls project:dataset

# Get table schema
bq show --schema --format=json project:dataset.table
```

**Cost awareness**: Charged per bytes scanned. Use `--dry_run`, partition tables, specify columns.

## GCP (gcloud)

```bash
# List resources
gcloud compute instances list --format=json

# Describe resource
gcloud compute instances describe INSTANCE --zone=ZONE --format=json

# Create with explicit project
gcloud compute instances create NAME --project=PROJECT --zone=ZONE

# Use --quiet for automation
gcloud compute instances delete NAME --quiet
```

## AWS

```bash
# List resources
aws ec2 describe-instances --output json

# With JMESPath filtering
aws ec2 describe-instances --query 'Reservations[].Instances[].InstanceId' --output text

# Explicit region
aws s3 ls s3://bucket --region us-west-2

# Dry run where available
aws ec2 run-instances --dry-run ...
```

## References

- [GCP.md](GCP.md) - GCP service patterns and common commands
- [AWS.md](AWS.md) - AWS service patterns and common commands
- [scripts/](scripts/) - Helper scripts for common operations

---

## Gotchas

- **`gcloud auth login` and `gcloud auth application-default login` are DIFFERENT credentials** — a script working for the user can 401 in CI because CI only has the latter.
- **AWS CLI v1 vs v2 have different config formats** — both may be installed; `aws --version` reveals which is the default `aws` binary.
- **BigQuery cost estimation requires `--dry_run`** — without it, you can run a $100 query thinking it's free. Always estimate first.
- **Precedence**: `AWS_PROFILE` vs `--profile` flag vs `AWS_ACCESS_KEY_ID` direct env — three-way precedence is order-dependent and rarely documented.
- **gcloud impersonation chains via `--impersonate-service-account` need IAM token-creator on EACH hop** — missing one hop returns 403 with vague "permission denied".
- **`aws sts get-caller-identity` is the cheapest way to verify which credential you're actually using** — always check first.