# CLI Reference
Complete command-line interface reference for Kelora. For quick start examples, see the [Quickstart Guide](../quickstart.md).
## Synopsis
```bash
kelora [OPTIONS] [FILES]...
```
## Processing Modes
Kelora supports two processing modes:
| **Sequential (default)** | Streaming, interactive, ordered output | Events processed one at a time in order |
| **Parallel (`--parallel`)** | High-throughput batch processing | Events processed in parallel batches across cores |
## Common Examples
```bash
# Find errors in access logs
kelora access.log --levels error,critical
# Transform JSON logs with Rhai
kelora -j app.json --exec 'e.duration_ms = e.end_time - e.start_time'
# Extract specific fields from NGINX logs
kelora nginx.log -f combined --keys method,status,path
```
## Arguments
### Files
```bash
[FILES]...
```
Input files to process. If omitted, reads from stdin. Use `-` to explicitly specify stdin.
**Examples:**
```bash
kelora app.log # Single file
kelora logs/*.jsonl # Multiple files with glob
kelora file1.log file2.log # Multiple files explicit
```
## Global Options
### Help and Version
| `-h, --help` | Print complete help (use `-h` for summary) |
| `-V, --version` | Print version information |
### Help Topics
| `--help-rhai` | Rhai scripting guide and stage semantics |
| `--help-functions` | All 150+ built-in Rhai functions |
| `--help-examples` | Practical log analysis patterns |
| `--help-time` | Timestamp format reference (chrono format strings) |
| `--help-multiline` | Multi-line event detection strategies |
## Input Options
### Format Selection
#### `-f, --input-format <FORMAT>`
Specify input format. Supports standard formats, column parsing, and CSV with type annotations.
**Standard Formats:**
- `json` - JSON lines (one JSON object per line)
- `line` - Plain text (default, one line per event)
- `csv` - CSV with header row
- `tsv` - Tab-separated values with header
- `logfmt` - Key-value pairs (logfmt format)
- `syslog` - Syslog RFC5424 and RFC3164
- `combined` - Apache/Nginx log formats (Common + Combined)
- `cef` - ArcSight Common Event Format
- `auto` - Auto-detect format
**Column Parsing:**
```bash
-f 'cols:timestamp(2) level *message'
```
**CSV with Types:**
```bash
-f 'csv status:int bytes:int response_time:float'
```
**Examples:**
```bash
kelora -f json app.log
kelora -f combined nginx.log
kelora -f 'cols:ts(2) level *msg' custom.log # `ts` is auto-detected as a timestamp
```
#### `-j`
Shortcut for `-f json`. Only affects input parsing. For JSON output, use `-J` or `-F json`.
```bash
kelora -j app.jsonl
# Equivalent to: kelora -f json app.jsonl
```
### File Processing
#### `--file-order <FILE_ORDER>`
Control file processing order.
**Values:**
- `cli` - Process files in command-line order (default)
- `name` - Sort files alphabetically by name
- `mtime` - Sort files by modification time (oldest first)
```bash
kelora --file-order mtime logs/*.log
```
### Line Filtering
#### `--skip-lines <N>`
Skip the first N input lines.
```bash
kelora --skip-lines 10 app.log
```
#### `--keep-lines <REGEX>`
Keep only input lines matching regex pattern (applied before `--ignore-lines`).
```bash
#### `--ignore-lines <REGEX>`
Ignore input lines matching regex pattern.
```bash
kelora --ignore-lines '^#' app.log # Skip comments
```
### Section Selection
Process specific sections of log files with multiple logical sections.
#### `--section-from <REGEX>`
Start emitting a section from the line that matches (inclusive). Without a stop flag, processing continues until EOF or the next occurrence of the start pattern.
```bash
kelora --section-from '^== iked Logs' system.log
```
#### `--section-after <REGEX>`
Begin the section after the matching line (exclusive start). Useful when headers are just markers.
```bash
kelora --section-after '^== HEADER' --section-before '^==' app.log
```
#### `--section-before <REGEX>`
Stop the section when the regex matches (exclusive end). This mirrors the previous `--section-end` behavior.
```bash
kelora --section-from '^== iked Logs' --section-before '^==' system.log
```
#### `--section-through <REGEX>`
Stop only after emitting the matching line (inclusive end). Handy when the footer carries status information.
```bash
kelora --section-from '^BEGIN' --section-through '^END$' build.log
```
#### `--max-sections <N>`
Maximum number of sections to process. Default: -1 (unlimited).
```bash
# Process first 2 sections
kelora --section-from '^== ' --max-sections 2 system.log
# Process only first section
kelora --section-from '^Session' --section-before '^End' --max-sections 1 app.log
```
**Processing Order:**
Section selection runs early in the pipeline, before `--keep-lines` and `--ignore-lines`:
1. `--skip-lines` - Skip first N lines
2. **`--section-from/after/before/through`** - Select sections
3. `--keep-lines` - Keep matching lines within sections
4. `--ignore-lines` - Ignore matching lines within sections
5. `-M/--multiline` - Group lines into events
6. Parsing - Parse into structured events
**Use Cases:**
```bash
# Extract specific service logs from docker-compose output
# Process first 3 user sessions
kelora --section-from 'User .* logged in' --section-through 'logged out' --max-sections 3 app.log
# Extract iked section, then filter for errors
kelora --section-after '^== iked' --section-before '^==' --keep-lines 'ERROR' system.log
```
**Performance:**
- Section selection is single-threaded (even with `--parallel`)
- Minimal overhead - just regex matching per line
- Heavy processing (parsing, filtering, Rhai) still parallelizes
- No full-file buffering - processes line-by-line
### Timestamp Configuration {#timestamp-options}
#### `--ts-field <FIELD>`
Custom timestamp field name for parsing. When set, Kelora only inspects that field; the built-in fallbacks are disabled so missing or malformed values stay visible in stats and diagnostics.
```bash
kelora -j --ts-field created_at app.log
```
#### `--ts-format <FORMAT>`
Custom timestamp format using chrono format strings. See `--help-time` for format reference.
```bash
kelora --ts-format '%Y-%m-%d %H:%M:%S' app.log
kelora --ts-format '%d/%b/%Y:%H:%M:%S %z' access.log
```
#### `--input-tz <TIMEZONE>`
Timezone for naive input timestamps (without timezone info). Default: UTC.
**Values:**
- `UTC` - Coordinated Universal Time
- `local` - System local time
- Named timezones: `Europe/Berlin`, `America/New_York`, etc.
```bash
kelora --input-tz local app.log
kelora --input-tz Europe/Berlin app.log
```
### Multi-line Events
#### `-M, --multiline <STRATEGY>`
Multi-line event detection strategy. Value format: `<strategy>[:key=value[:key=value...]]`. Supported strategies:
- `timestamp` — optional `format=` hint (e.g., `timestamp:format=%Y-%m-%d %H-%M-%S`)
*(Literal `:` characters in the format string are not supported yet.)*
- `indent`
- `regex` — requires `match=REGEX`, optional `end=REGEX`
- `all`
```bash
kelora -M all config.json # Entire input as one event
kelora -M timestamp app.log # Auto-detect timestamp headers
kelora -M 'timestamp:format=%Y-%m-%d %H-%M-%S' app.log
kelora -M 'regex:match=^\\d{4}-' app.log # Start pattern only
kelora -M 'regex:match=^START:end=^END$' app.log # Start + end patterns
```
### Prefix Extraction
#### `--extract-prefix <FIELD>`
Extract text before separator to specified field (runs before parsing).
```bash
#### `--prefix-sep <STRING>`
Separator string for prefix extraction. Default: `|`
```bash
kelora --extract-prefix node --prefix-sep ' :: ' cluster.log
```
### Column Format Options
#### `--cols-sep <SEPARATOR>`
Column separator for `cols:<spec>` format. Default: whitespace.
```bash
kelora -f 'cols:name age city' --cols-sep ',' data.txt
```
## Processing Options
### Scripting Stages
#### `--begin <SCRIPT>`
Run Rhai script once before processing any events. Typical use: initialize lookup tables or shared context in the global `conf` map.
**Available helpers:**
- `read_lines(path)` - Read file as array of lines
- `read_file(path)` - Read file as string
```bash
kelora -j --begin 'conf.users = read_json("users.json")' app.log
```
#### `--filter <EXPRESSION>`
Boolean filter expression. Events where expression returns `true` are kept. Multiple filters are combined with AND logic.
```bash
kelora -j --filter 'e.status >= 400' app.log
kelora -j --filter 'e.service == "api"' --filter 'e.level == "ERROR"' app.log
```
#### `-e, --exec <SCRIPT>`
Transform/process script evaluated on each event. Multiple `--exec` scripts run in order.
```bash
kelora -j --exec 'e.duration_s = e.duration_ms / 1000' app.log
kelora -j --exec 'track_count(e.service)' app.log
```
#### `-E, --exec-file <FILE>`
Execute Rhai script from file (runs in exec stage).
```bash
kelora -j -E transform.rhai app.log
```
#### `-I, --include <FILE>`
Include Rhai files before script stages (library imports).
```bash
kelora -j -I helpers.rhai --exec 'e.custom = my_helper(e)' app.log
```
#### `--end <SCRIPT>`
Run once after processing completes (post-processing stage). Access global `metrics` map from `track_*()` calls here.
```bash
kelora -j \
--exec 'track_count(e.service)' \
--end 'print("Total services: " + metrics.len())' \
app.log
```
### Span Aggregation
#### `--span <N | DURATION | FIELD>`
Group events into non-overlapping spans before running a span-close hook. Sequential mode is required (Kelora prints a warning and falls back to sequential if `--parallel` is also supplied).
- `--span <N>` – Count-based spans. Close after every **N** events that survive all filters. Example: `--span 500`.
- `--span <DURATION>` – Time-based spans aligned to the events' canonical timestamp (`ts`). The first event with a valid `ts` anchors fixed windows such as `1m`, `5m`, `30s`, `1h`.
- `--span <FIELD>` – Field-based spans. Open a new span whenever the field value changes. With the single-active-span model, interleaved IDs (`req-1, req-2, req-1`) produce multiple spans per ID.
How it works:
- Per-event scripts still run for every event.
- Events missing a timestamp (time mode) are marked `meta.span_status == "unassigned"` and excluded from the span buffer.
- Events with timestamps that fall into an already-closed window are emitted immediately with `meta.span_status == "late"`. Closed spans are never reopened.
- Count spans keep buffered events in memory until the span closes. Kelora warns when `N > 100_000`.
- Field spans continue the current span when the field is missing (error with `--strict`).
#### `--span-idle <DURATION>`
Close spans after a period of inactivity (no events). Requires timestamps and cannot be combined with `--span`.
- Opens a span on the first event with a timestamp; closes when the forward gap between events exceeds the timeout.
- Span IDs use `idle-#<seq>-<start_timestamp>`.
- Missing timestamps: tagged `unassigned` (errors with `--strict`).
- Interleaved/out-of-order events do not close spans; only forward-time gaps are considered. Sort input if you need strict wall-clock ordering.
#### `--span-close <SCRIPT>`
Run a Rhai snippet once whenever a span closes. Use it to emit per-span summaries, metrics, or rollups. The script runs after the event that triggered the close finishes all per-event stages (filters, execs, etc.).
**Read-only span object available inside `--span-close`:**
- `span.id` – Unique span identifier (`#0`, `2024-05-19T12:00:00Z/5m`, etc.)
- `span.start` / `span.end` – Half-open window bounds for time-based spans (count spans return `()`)
- `span.size` – Number of events that survived filters and were included in this span
- `span.events` – Array of events in arrival order (each map includes `span_status`, `span_start`, etc.)
- `span.metrics` – Map of per-span deltas from `track_*` calls (automatically reset after each span)
**Metadata added to `meta` during per-event stages:**
- `meta.span_status` – `"included"`, `"late"`, `"unassigned"`, or `"filtered"`
- `meta.span_id` – Span identifier (`null` for unassigned events)
- `meta.span_start`, `meta.span_end` – Boundaries as DateTime values (or `()` when not applicable)
Kelora cleans up span state automatically when processing completes or on graceful shutdown.
### File System Access
#### `--allow-fs-writes`
Allow Rhai scripts to create directories and write files. Required for file helpers like `append_file()` or `mkdir()`.
```bash
kelora -j --allow-fs-writes --exec 'append_file("errors.txt", e.message)' app.log
```
### Window Functions
#### `--window <SIZE>`
Enable sliding window of N+1 recent events. The window is exposed as the `window` array, so you can call helpers like `window.pluck()`.
```bash
kelora -j --window 5 --exec 'e.recent_statuses = window.pluck("status")' app.log
```
### Timestamp Conversion
#### `--normalize-ts`
Normalize the primary timestamp field (the one Kelora uses for filtering and stats) to RFC3339 (ISO 8601). Runs after Rhai scripts and affects every output formatter.
```bash
kelora -j --normalize-ts app.log
```
## Error Handling Options
### Strict Mode
#### `--strict`
Exit on first error (fail-fast behavior). Parsing errors, filter errors, or exec errors will immediately abort processing.
```bash
kelora -j --strict app.log
```
#### `--no-strict`
Disable strict mode explicitly (resilient mode is default).
### Verbosity
#### `-v, --verbose`
Show detailed error information. Use multiple times for more verbosity: `-v`, `-vv`, `-vvv`.
```bash
kelora -j --verbose app.log
```
### Output/Quiet Controls
#### `-q` / `--no-events`
Suppress formatter output (events). Diagnostics, stats, metrics, and script output remain unless further flags are used. Same effect as `-F none`.
```bash
kelora -q app.log # No events, diagnostics still emit
kelora --no-events -s -m app.log # Stats + metrics, no events
```
#### `--no-diagnostics`
Suppress diagnostics and error summaries; a single fatal line is still emitted on errors. Does not affect events.
```bash
kelora -q --no-diagnostics app.log # No events, no diagnostics
```
#### `--silent` / `--no-silent`
Suppress pipeline emitters on stdout/stderr (events, diagnostics, stats, terminal metrics). Script output stays enabled unless you also use `--no-script-output` or data-only modes. Metrics files still write. A single fatal line is emitted on errors. `--no-silent` disables a silent default from config.
```bash
kelora --silent --metrics-file out.json app.log # Quiet terminal, metrics file written
```
#### `--no-script-output`
Suppress Rhai `print`/`eprint` and side-effect warnings without affecting diagnostics/stats/metrics. Implied by data-only modes (`-s`, `-m` without `--with-*` flags).
## Filtering Options
### Level Filtering
#### `-l, --levels <LEVELS>`
Include only events with specified log levels (case-insensitive). Every occurrence runs exactly where it appears in the CLI, so you can place `-l` before heavy `--exec` stages (to prune work early) or repeat it later after you derive a new level.
```bash
kelora -j --levels error app.log
kelora -j --levels error,warn,critical app.log
kelora -j --exec 'if !e.has("level") { e.level = "WARN" }' --levels warn log.txt # Add level, then filter
```
#### `-L, --exclude-levels <LEVELS>`
Exclude events with specified log levels (case-insensitive). Like `--levels`, you may repeat this flag to drop different levels at multiple points in the pipeline.
```bash
kelora -j --exclude-levels debug,trace app.log
kelora -j --levels error --exec 'if e.service == "chat" { e.level = "WARN" }' \
--exclude-levels warn app.log
```
### Field Selection
#### `-k, --keys <FIELDS>`
Output only specified top-level fields (comma-separated list).
```bash
kelora -j --keys timestamp,level,message app.log
```
#### `-K, --exclude-keys <FIELDS>`
Exclude specified fields from output (comma-separated list).
```bash
kelora -j --exclude-keys password,token,secret app.log
```
### Time Range Filtering
#### `--since <TIME>`
Include events from this time onward. Accepts journalctl-style timestamps.
**Formats:**
- Absolute: `2024-01-15T12:00:00Z`, `2024-01-15 12:00`, `10:30:00`
- Relative: `1h`, `-30m`, `yesterday`, `now`, `today`
- Anchored: `end+1h`, `end-30m` (relative to `--until` value)
```bash
kelora -j --since '1 hour ago' app.log
kelora -j --since yesterday app.log
kelora -j --since 2024-01-15T10:00:00Z app.log
# Duration before end time
kelora -j --since "end-1h" --until "11:00" app.log
```
**See Also:** [Time Reference](time-reference.md#time-range-filtering) for complete timestamp syntax.
#### `--until <TIME>`
Include events until this time. Accepts journalctl-style timestamps.
**Formats:**
- Absolute: `2024-01-15T12:00:00Z`, `2024-01-15 12:00`, `18:00:00`
- Relative: `1h`, `+30m`, `tomorrow`, `now`
- Anchored: `start+30m`, `start-1h` (relative to `--since` value)
```bash
kelora -j --until '30 minutes ago' app.log
kelora -j --until tomorrow app.log
kelora -j --until 2024-01-15T18:00:00Z app.log
# Duration after start time
kelora -j --since "10:00" --until "start+30m" app.log
```
**Anchored Timestamp Examples:**
Anchor one boundary to the other for duration-based windows:
```bash
# 30 minutes starting at 10:00
kelora --since "10:00" --until "start+30m" app.log
# 1 hour ending at 11:00
kelora --since "end-1h" --until "11:00" app.log
# 2 hours starting from yesterday
kelora --since "yesterday" --until "start+2h" app.log
```
**Important:** Cannot use both anchors in the same command (e.g., `--since end-1h --until start+1h` is an error).
**See Also:** [Time Reference](time-reference.md#time-range-filtering) for complete timestamp syntax.
### Output Limiting
#### `-n, --take <N>`
Limit output to the first N events (after filtering).
```bash
kelora -j --take 100 app.log
kelora -j --levels error --take 10 app.log
```
### Context Lines
#### `-B, --before-context <N>`
Show N lines before each match (requires filtering with `--filter` or `--levels`).
```bash
kelora -j --levels error --before-context 2 app.log
```
#### `-A, --after-context <N>`
Show N lines after each match (requires filtering).
```bash
kelora -j --levels error --after-context 3 app.log
```
#### `-C, --context <N>`
Show N lines before and after each match (requires filtering).
```bash
kelora -j --levels error --context 2 app.log
```
**Visual Example:**
Context lines are highlighted with colored symbols: `/` for before-context, `*` for matching lines, `\` for after-context, and `|` for separator lines.
## Output Options
### Output Format
#### `-F, --output-format <FORMAT>`
Output format. Default: `default`
**Values:**
- `default` - Key-value format with colors
- `json` - JSON lines (one object per line)
- `logfmt` - Key-value pairs (logfmt format)
- `inspect` - Debug format with type information
- `levelmap` - Grouped by log level
- `csv` - CSV with header
- `tsv` - Tab-separated values with header
- `csvnh` - CSV without header
- `tsvnh` - TSV without header
- `none` - No event output (only metrics/stats)
```bash
kelora -j -F json app.log
kelora -j -F csv app.log
kelora -j -F none --stats app.log
```
#### `-J`
Shortcut for `-F json`.
```bash
kelora -j -J app.log
# Equivalent to: kelora -f json -F json app.log
```
### Output Destination
#### `-o, --output-file <FILE>`
Write formatted events to file instead of stdout.
```bash
kelora -j -F json -o output.json app.log
```
### Core Fields
#### `-c, --core`
Output only core fields (timestamp, level, message).
```bash
kelora -j --core app.log
```
## Default Format Options
These options only affect the default formatter (`-F default`).
### Brief Mode
#### `-b, --brief`
Output only field values (omit field names).
```bash
kelora -j --brief app.log
```
### Nested Structures
#### `--expand-nested`
Expand nested structures (maps/arrays) with indentation.
```bash
kelora -j --expand-nested app.log
```
### Word Wrapping
#### `--wrap`
Enable word-wrapping (default: on).
#### `--no-wrap`
Disable word-wrapping (overrides `--wrap`).
```bash
kelora -j --no-wrap app.log
```
### Timestamp Display
#### `-z, --show-ts-local`
Display timestamps as local RFC3339 (ISO 8601 compatible). Display-only - only affects default formatter output.
```bash
kelora -j -z app.log
# Output: 2024-01-15T10:30:00+01:00
```
#### `-Z, --show-ts-utc`
Display timestamps as UTC RFC3339 (ISO 8601 compatible). Display-only - only affects default formatter output.
```bash
kelora -j -Z app.log
# Output: 2024-01-15T09:30:00Z
```
## Display Options
### Colors
#### `--force-color`
Force colored output (even when piping to file).
```bash
kelora -j --force-color app.log > output.txt
```
#### `--no-color`
Disable colored output.
```bash
kelora -j --no-color app.log
```
### Gap Markers
#### `--mark-gaps <DURATION>`
Insert centered marker when time delta between events exceeds duration.
```bash
kelora -j --mark-gaps 30s app.log # Mark 30+ second gaps
kelora -j --mark-gaps 5m app.log # Mark 5+ minute gaps
```
**Visual Example:**
Gap markers help identify time discontinuities in your logs, making it easier to spot service restarts, network issues, or other temporal anomalies.
### Emoji
#### `--no-emoji`
Disable emoji prefixes in output.
```bash
kelora -j --no-emoji app.log
```
## Performance Options
### Parallel Processing
#### `--parallel`
Enable parallel processing across multiple cores. Higher throughput, may reorder output.
```bash
kelora -j --parallel app.log
```
#### `--no-parallel`
Disable parallel processing explicitly (sequential mode is default).
#### `--threads <N>`
Number of worker threads for parallel processing. Default: 0 (auto-detect cores).
```bash
kelora -j --parallel --threads 4 app.log
```
#### `--batch-size <N>`
Batch size for parallel processing. Larger batches improve throughput but increase memory usage.
```bash
kelora -j --parallel --batch-size 5000 app.log
```
#### `--batch-timeout <MS>`
Flush partially full batches after idle period (milliseconds). Lower values reduce latency; higher values improve throughput.
Default: 200ms
```bash
kelora -j --parallel --batch-timeout 100 app.log
```
#### `--unordered`
Disable ordered output for maximum parallel performance.
```bash
kelora -j --parallel --unordered app.log
```
## Metrics and Statistics
### Statistics
#### `-s, --stats[=FORMAT]`
Show stats only (suppress events). Use `-s` for default table format, or `--stats=FORMAT` for explicit format.
Formats: `table`, `json`
```bash
kelora -j -s app.log # Default table format
kelora -j --stats=json app.log # JSON format
```
#### `--with-stats`
Show stats alongside events (rare case).
```bash
kelora -j --with-stats app.log
```
#### `--no-stats`
Disable processing statistics explicitly (default: off).
### Tracked Metrics
#### `-m, --metrics[=FORMAT]`
Show metrics only (suppress events). Use `-m` for default table format, or `--metrics=FORMAT` for explicit format.
Formats: `table`, `full`, `json`
```bash
kelora -j --exec 'track_count(e.service)' -m app.log # Default table
kelora -j --exec 'track_count(e.service)' --metrics=full app.log # Full table
kelora -j --exec 'track_count(e.service)' --metrics=json app.log # JSON format
```
#### `--with-metrics`
Show metrics alongside events (rare case).
```bash
kelora -j --exec 'track_count(e.service)' --with-metrics app.log
```
#### `--no-metrics`
Disable tracked metrics explicitly (default: off).
#### `--metrics-file <FILE>`
Persist metrics map to disk as JSON.
```bash
kelora -j --exec 'track_count(e.service)' --metrics-file metrics.json app.log
```
## Configuration Options
### Configuration File
Kelora uses a configuration file for defaults and aliases. See [Configuration System](../concepts/configuration-system.md) for details.
#### `-a, --alias <ALIAS>`
Use alias from configuration file.
```bash
kelora -a errors app.log
```
#### `--config-file <FILE>`
Specify custom configuration file path.
```bash
kelora --config-file /path/to/custom.ini app.log
```
#### `--show-config`
Show current configuration with precedence information and exit.
```bash
kelora --show-config
```
#### `--edit-config`
Edit configuration file in default editor and exit.
```bash
kelora --edit-config
```
#### `--ignore-config`
Ignore configuration file (use built-in defaults only).
```bash
kelora --ignore-config app.log
```
#### `--save-alias <NAME>`
Save current command as alias to configuration file.
```bash
kelora -j --levels error --keys timestamp,message --save-alias errors
# Later use: kelora -a errors app.log
```
## Exit Codes
Kelora uses standard Unix exit codes to indicate success or failure:
| `0` | Success - no errors occurred |
| `1` | Processing errors (parse/filter/exec errors) |
| `2` | Usage errors (invalid flags, file not found, config errors) |
| `130` | Interrupted (Ctrl+C / SIGINT) |
| `141` | Broken pipe (SIGPIPE - normal in pipelines) |
| `143` | Terminated (SIGTERM) |
For detailed information on exit codes, error handling modes, scripting patterns, and troubleshooting, see the [Exit Codes Reference](exit-codes.md).
## Environment Variables
### Configuration
- **`TZ`** - Default timezone for naive timestamps (overridden by `--input-tz`)
### Rhai Scripts
Access environment variables in scripts using `get_env()`:
```bash
kelora -j --exec 'e.build = get_env("BUILD_ID", "unknown")' app.log
```
## Common Option Combinations
### Error Analysis
```bash
# Find errors with context
kelora -j --levels error --context 2 app.log
# Count errors by service
kelora -j --levels error --exec 'track_count(e.service)' --metrics app.log
```
### Performance Analysis
```bash
# Find slow requests
kelora -f combined --filter 'e.request_time.to_float() > 1.0' nginx.log
# Track response time percentiles
kelora -f combined \
--exec 'track_bucket("latency", e.request_time.to_float() * 1000)' \
--metrics nginx.log
```
### Data Export
```bash
# Export to JSON
kelora -j -F json -o output.json app.log
# Export to CSV
kelora -j -F csv --keys timestamp,level,service,message -o report.csv app.log
```
### Real-Time Monitoring
=== "Linux/macOS"
```bash
tail -f app.log | kelora -j -l error,warn
```
=== "Windows"
```powershell
Get-Content -Wait app.log | kelora -j -l error,warn
```
### High-Performance Batch Processing
```bash
# Parallel processing with optimal batch size
kelora -j --parallel --batch-size 5000 --unordered large.log
# Compressed archives
kelora -j --parallel logs/*.log.gz
```
## See Also
- [Quickstart Guide](../quickstart.md) - Get started in 5 minutes
- [Function Reference](functions.md) - All 150+ built-in Rhai functions
- [Pipeline Model](../concepts/pipeline-model.md) - How processing stages work
- [Configuration System](../concepts/configuration-system.md) - Configuration files and aliases