uutils/sed

POSIX mode incorrectly rejects i\(text) format

Open

#252 opened on Jan 11, 2026

View on GitHub
 (3 comments) (0 reactions) (0 assignees)Rust (23 forks)github user discovery
good first issue

Repository metrics

Stars
 (91 stars)
PR merge metrics
 (Avg merge 6d 9h) (25 merged PRs in 30d)

Description

Rust (incorrect - returns error)

$ echo "test" | cargo run --quiet -- -n --posix -e 'i\(text'
 # Error: sed: <script argument 1>:1:3: error: extra characters after \ at the end of `i' command
 # Exit code: 1

GNU (correct)

  $ echo "test" | /usr/bin/sed -n --posix -e 'i\(text'
  # Output: (text
  # Exit code: 0

Bug Found by Fuzzer

Contributor guide

Research direction
Examine the parser for the 'i' command in POSIX mode to understand why it rejects the escaped parentheses despite GNU sed accepting it.
Tech stack
rust
Domain
cli
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Rustsed
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75