Modern Cli

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34 cards — 🟢 11 easy | 🟡 7 medium | 🔴 7 hard

🟢 Easy (11)

1. What does fd replace and what is its key advantage?

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fd replaces find. Key advantages: respects .gitignore by default, regex patterns, colorized output, simpler syntax. Example: fd -e yaml finds all YAML files vs find . -name '*.yaml' -type f

Remember: fd = modern find. Smart case, colorized, .gitignore-aware. Simpler syntax.

2. What does rg (ripgrep) replace and why is it faster?

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rg replaces grep -r. Faster because: multi-threaded, respects .gitignore, uses optimized regex engine (Rust). Automatically skips binary files and .git directories.

Remember: rg = faster grep. .gitignore-aware, recursive default, highlights. Rust-powered.

3. What is fzf and what problem does it solve?

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fzf is an interactive fuzzy finder. Turns any list into a searchable, selectable menu. Pipe anything into it: kubectl get pods | fzf, git branch | fzf, history | fzf. Transforms CLI workflows from recall-based to recognition-based.

Remember: fzf = fuzzy finder. Pipe anything: `history | fzf`. Ctrl+R = game-changer.

Example: `FZF_DEFAULT_COMMAND='fd --type f'` uses fd for file search.

4. What is jq and when do you reach for it?

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jq is a command-line JSON processor. Use whenever you get JSON output: kubectl -o json, AWS CLI, Terraform state, API responses. Basic patterns: jq '.' (pretty-print), jq '.key' (extract), jq '.[] | .name' (iterate).

Remember: jq = JSON processor. Essential for APIs. `curl url | jq '.data[] | .name'`.

Example: `jq -r '.items[] | [.name, .status] | @tsv'` — JSON to TSV.

5. What is yq and how does it relate to jq?

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yq is jq for YAML (and TOML). Same filter syntax, works on YAML files directly. Essential for editing Kubernetes manifests, Helm values, and CI configs. Example: yq '.spec.replicas' deployment.yaml

Remember: jq = JSON processor. Essential for APIs. `curl url | jq '.data[] | .name'`.

Example: `jq -r '.items[] | [.name, .status] | @tsv'` — JSON to TSV.

6. What does eza replace and what does it add over ls?

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eza replaces ls. Adds: colorized output by file type, built-in tree view (eza --tree), git status per file (eza -la --git), and icon support. Useful: eza --sort modified for recently changed files.

Remember: exa/eza = modern ls. Colors, git status, tree. `exa -la --git`.

7. What does bat replace and what does it add over cat?

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bat replaces cat. Adds: syntax highlighting, line numbers, git diff markers, and automatic paging. Use bat -l yaml to force language. Set as MANPAGER for colorized man pages: export MANPAGER='bat -l man -p'

Remember: bat = cat + syntax highlighting + line numbers + git. Drop-in replacement.

8. What is delta and how do you set it up with git?

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delta is a syntax-highlighting diff viewer. Add to .gitconfig: [core] pager = delta. Provides side-by-side view (delta -s), line numbers, and language-aware highlighting for git diff, git log -p, and git show.

Remember: delta = better git diff. Highlighting, line numbers. `git config core.pager delta`.

9. What does zoxide replace and how does it learn?

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zoxide replaces cd. It learns from your navigation — tracks directory frequency and recency (frecency). z exercises jumps to most-visited match. zi opens interactive selection with fzf. Setup: eval \$(zoxide init bash)\""

Remember: zoxide = smart cd. Learns habits. `z proj` → /home/user/projects.

10. What does dust replace and what does it add over du?

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dust replaces du. Provides visual bar charts of disk usage, sorted by size, with automatic depth. dust -n 20 shows top 20 entries. dust -d 2 limits depth. No need to pipe through sort -rh | head like with du.

Remember: Modern CLI = Rust-powered: rg, fd, bat, exa, delta, zoxide. Faster, friendlier.

Example: Replace: grep→rg, find→fd, cat→bat, ls→exa, cd→zoxide, diff→delta.

11. When do you still use classic tools (grep, find, cat) over modern ones?

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On remote servers without modern tools installed. In shell scripts that must be portable. In Dockerfiles (minimize image size). When piping to other programs that expect standard output format. Know both — modern for interactive work, classic for portability.

Remember: Modern CLI = Rust-powered: rg, fd, bat, exa, delta, zoxide. Faster, friendlier.

Example: Replace: grep→rg, find→fd, cat→bat, ls→exa, cd→zoxide, diff→delta.

🟡 Medium (7)

1. How do you find and execute a command on matching files with fd?

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fd -e py -x wc -l (count lines in each Python file). fd -e log -X rm (delete all .log files — -X batches into one command, -x runs per file). Add -H to include hidden files.

Remember: fd = modern find. Smart case, colorized, .gitignore-aware. Simpler syntax.

2. How do you search only specific file types with rg?

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rg 'pattern' -t yaml (built-in type filter). rg 'pattern' -g '*.yaml' (glob filter). rg -t py -g '!test*' 'pattern' (Python files excluding tests). rg --type-list shows all built-in types.

Remember: rg = faster grep. .gitignore-aware, recursive default, highlights. Rust-powered.

3. What are the three key fzf shell keybindings?

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Ctrl-R: fuzzy search command history. Ctrl-T: fuzzy find and insert a file path. Alt-C: fuzzy cd into a subdirectory. Enable with: eval \$(fzf --bash)\" in .bashrc (or --zsh/--fish)."

Remember: fzf = fuzzy finder. Pipe anything: `history | fzf`. Ctrl+R = game-changer.

Example: `FZF_DEFAULT_COMMAND='fd --type f'` uses fd for file search.

4. How do you filter and reshape JSON with jq?

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Filter: jq '.items[] | select(.status == \running\")'. Reshape: jq '{name: .metadata.name, phase: .status.phase}'. Raw output: jq -r '.name' (no quotes). Slurp: jq -s '.' (read all inputs into array)."

Remember: jq = JSON processor. Essential for APIs. `curl url | jq '.data[] | .name'`.

Example: `jq -r '.items[] | [.name, .status] | @tsv'` — JSON to TSV.

5. How do you modify a YAML file in-place with yq?

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yq -i '.spec.replicas = 3' deployment.yaml. Add a field: yq -i '.metadata.labels.env = \prod\"' deployment.yaml. Delete: yq -i 'del(.spec.template.metadata.annotations)' deployment.yaml."

Remember: Modern CLI = Rust-powered: rg, fd, bat, exa, delta, zoxide. Faster, friendlier.

Example: Replace: grep→rg, find→fd, cat→bat, ls→exa, cd→zoxide, diff→delta.

6. How do you use bat as a previewer for other tools?

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With fzf: fzf --preview 'bat --color=always {}'. With git: git diff | bat -l diff. As pager: export BAT_PAGER='less -RF'. bat -A shows whitespace characters (tabs, spaces, newlines).

Remember: bat = cat + syntax highlighting + line numbers + git. Drop-in replacement.

7. What is the modern-tool equivalent of 'find . -name *.yaml | xargs grep replicas | sort'?

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rg 'replicas' -t yaml. One command replaces the entire pipeline. Add -C 2 for context, -l for file names only, --stats for totals. rg handles .gitignore, binary files, and multi-threading automatically.

Remember: rg = faster grep. .gitignore-aware, recursive default, highlights. Rust-powered.

🔴 Hard (7)

1. How do you use rg to find files containing a string and show context?

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rg 'error_handler' -C 3 (3 lines before and after). rg -l 'error_handler' (file names only). rg -c 'error_handler' (count per file). --stats flag adds summary totals.

Remember: rg = faster grep. .gitignore-aware, recursive default, highlights. Rust-powered.

2. How do you combine fzf with file preview?

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rg --files | fzf --preview 'bat --color=always {}' — browse files with syntax-highlighted preview. For git: git log --oneline | fzf --preview 'git show {1}' — preview commits interactively.

Remember: fzf = fuzzy finder. Pipe anything: `history | fzf`. Ctrl+R = game-changer.

Example: `FZF_DEFAULT_COMMAND='fd --type f'` uses fd for file search.

3. How do you count and aggregate with jq?

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Count: jq '.items | length'. Group and count: jq '[.items[] | .status.phase] | group_by(.) | map({(.[0]): length}) | add'. TSV output: jq -r '[.timestamp, .service, .message] | @tsv'

Remember: jq = JSON processor. Essential for APIs. `curl url | jq '.data[] | .name'`.

Example: `jq -r '.items[] | [.name, .status] | @tsv'` — JSON to TSV.

4. When should you use z vs zi vs cd?

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z for known frequent directories (z grok → /home/user/grokdevops). zi when multiple matches exist and you want to pick interactively. Plain cd for explicit paths or parent navigation (cd ..).

Remember: Modern CLI = Rust-powered: rg, fd, bat, exa, delta, zoxide. Faster, friendlier.

Example: Replace: grep→rg, find→fd, cat→bat, ls→exa, cd→zoxide, diff→delta.

5. How do you combine rg + fzf + bat for interactive code search?

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rg 'pattern' -l | fzf --preview 'bat --color=always -H $(rg -n \pattern\" {} | head -1 | cut -d: -f1) {}' — lists matching files, preview highlights the match line. Powerful for exploring unfamiliar codebases."

Remember: rg = faster grep. .gitignore-aware, recursive default, highlights. Rust-powered.

6. How do you use jq to triage JSON logs from an application?

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cat app.log | jq 'select(.level == \error\")' (filter errors). Count by service: jq -r 'select(.level == \"error\") | .service' | sort | uniq -c | sort -rn. Table output: jq -r '[.timestamp, .service, .message] | @tsv' | column -t"

Remember: jq = JSON processor. Essential for APIs. `curl url | jq '.data[] | .name'`.

Example: `jq -r '.items[] | [.name, .status] | @tsv'` — JSON to TSV.

7. You need to find all YAML files containing 'replicas' in a monorepo. Which tool chain do you pick?

Show answer

rg 'replicas' -t yaml for the answer. If you need to browse the results interactively: rg 'replicas' -t yaml -l | fzf --preview 'bat --color=always {}'. Classic equivalent takes 3+ commands; rg does it in one.

Remember: Modern CLI = Rust-powered: rg, fd, bat, exa, delta, zoxide. Faster, friendlier.

Example: Replace: grep→rg, find→fd, cat→bat, ls→exa, cd→zoxide, diff→delta.