`replace`

Performs string replacement in specified fields. Supports simple string replacement and regex-based replacement.

Write with --output. A trailing path is not a positional argument.

# Simple string replacement
undatum replace data.csv --field name --pattern "Mr\." --replacement "Mr" --output output.csv

# Regex replacement
undatum replace data.jsonl --field email --pattern "@old.com" --replacement "@new.com" --regex --output output.jsonl

# Global replacement (all occurrences; default is first match only)
undatum replace data.csv --field text --pattern "old" --replacement "new" --global-replace --output output.csv

--field, --pattern, --replacement
--regex — treat --pattern as regex
--global-replace — replace every match in the field (not --global)
--output — output path (stdout if omitted)

Also accepts --table, --flatten-nested, --on-error, --error-log, and --quotechar (shared options).

Reference

Reads: any readable format · Writes: any writable format; CSV/TSV/JSON/JSON Lines on stdout · Memory: streaming · Engines: auto, duckdb, python

undatum replace [OPTIONS] INPUT_FILE

Argument	Description
`INPUT_FILE`	Path to input file. (required)

Option	Description	Default
`-o`, `--output` TEXT	Optional output file path. If not specified, prints to stdout.
`--field` TEXT	Field name to perform replacement in.
`--pattern` TEXT	Pattern to search for (string or regex).
`--replacement` TEXT	Replacement string.
`--regex` / `--no-regex`	Treat pattern as regex.	`--no-regex`
`--global-replace` / `--no-global-replace`	Replace all occurrences (default: replace first only).	`--no-global-replace`
`-d`, `--delimiter` TEXT	CSV delimiter character (auto-detected when omitted).
`--quotechar` TEXT	CSV quote character (iterabledata default '"' when omitted).
`--encoding` TEXT	File encoding (e.g., 'utf8', 'latin1').
`--verbose` / `--no-verbose`	Enable verbose logging output.	`--no-verbose`
`-F`, `--format-in` TEXT	Override input file format detection (e.g., 'csv', 'jsonl').
`--table`, `--sheet` TEXT	Table or sheet name for multi-table sources (Excel, SQLite, lakehouse).
`--start-page` INTEGER	Sheet index (0-based) for Excel files.	`0`
`--trust`	Acknowledge pickle deserialization risk when reading pickle sources.
`--on-error` TEXT	Parse-error policy: raise (default), skip, or warn.
`--error-log` TEXT	Append parse errors as JSONL (use with --on-error skip or warn).
`--flatten-nested`	Unfold nested dict / array-of-dict fields into dotted paths (e.g. city.lat).
`--max-nested-depth` INTEGER	With --flatten-nested, maximum nest depth to unfold (engine default 5).
`--keep-nested-parents` / `--no-keep-nested-parents`	With --flatten-nested, keep parent dict/array fields alongside dotted children.	`--keep-nested-parents`
`-e`, `--engine` [auto\|duckdb\|python]	Processing engine: auto (default), duckdb, or python.
`-O`, `--format-out` TEXT	Output format (e.g. csv, jsonl, parquet). Defaults to the --output extension, or to the input's text format on stdout.

Reference​

Reference