Formatting Flags

rg outputs human-readable grouped results by default. These flags reshape the output for different consumers: scripts, editors, and monitoring pipelines.

Line Numbers (-n / -N)

rg includes line numbers by default. The flags let you toggle:

rg -n "TODO" src/     # (default) with line numbers
rg -N "TODO" src/     # without line numbers

Only Filenames (-l)

The most common output shaping flag. Returns only the names of files with at least one match, then stops reading each file:

# Which files contain "FIXME"?
rg -l "FIXME" src/

# Pass list to xargs for bulk operations
rg -l "old_api_v1" . | xargs sed -i 's/old_api_v1/new_api_v2/g'

Count Matches Per File (-c)

# How many TODOs are in each file?
rg -c "TODO" src/

# Output:
# src/app.py:3
# src/utils.py:1
# src/models.py:7

Print Only the Match (-o)

Like grep -o — discard the surrounding line and print only the exact matched substring. One match per line:

# Extract all IP addresses
rg -o "[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}" access.log | sort -u

# Extract all HTTP status codes
rg -o "HTTP/[0-9\.]+ \K[0-9]{3}" access.log | sort | uniq -c

JSON Output (--json)

rg --json outputs newline-delimited JSON (NDJSON). Every match, begin, end, and summary event is a JSON object — ideal for programmatic consumption.

rg --json "ERROR" app.log | jq 'select(.type == "match") | .data.lines.text'

Fields include: path, line_number, absolute_offset, lines, submatches.

Vimgrep Format (--vimgrep)

Outputs file:line:col:text format, which is directly compatible with Vim's copen quickfix list:

rg --vimgrep "TODO" src/ > /tmp/todo.txt
# In Vim:
# :cfile /tmp/todo.txt
# :copen

No Heading (--no-heading)

By default rg groups results under a filename header. Use --no-heading to get the traditional grep-style file:line:match format — required when piping to tools that expect that format.

rg --no-heading "pattern" . | cut -d: -f1 | sort -u