sd — Intuitive Find & Replace CLI, a Friendlier Alternative to sed

What it is

sd is a command-line find-and-replace tool written in Rust that serves as a simpler alternative to sed. It takes two arguments -- pattern and replacement -- and handles the common case of text substitution without sed's cryptic syntax, escaping rules, or BSD vs GNU behavioral differences.

sd targets developers and system administrators who use sed primarily for find-and-replace and want a tool that works the same way on every platform. The regex engine uses Rust's regex crate with Perl-like syntax, supporting non-greedy quantifiers, lookarounds, and named capture groups.

How it saves time or tokens

Sed requires escaping parentheses for capture groups in BRE mode, uses different flags on BSD (macOS) and GNU (Linux), and has a multi-letter command language that most users never need. sd eliminates all of this. The pattern is a regex, the replacement uses $1 $2 for capture groups, and in-place editing is a flag.

The preview flag (-p) shows what would change without modifying files, preventing accidental edits in scripts and CI pipelines.

How to use

1. Install sd:

# macOS
brew install sd
# Cargo
cargo install sd --locked

1. Basic find and replace from stdin:

echo 'hello world' | sd world everyone
# hello everyone

1. In-place file editing with regex:

# Replace version strings using capture groups
sd 'v(\d+)\.(\d+)\.(\d+)' 'version_$1_$2_$3' changelog.md

# Preview before applying
sd -p 'foo' 'bar' *.md

Example

Common sd recipes for development workflows:

# Rename a function across files
sd 'oldFunction' 'newFunction' src/*.go

# Fix import paths
sd 'github.com/old-org/repo' 'github.com/new-org/repo' **/*.go

# Literal string mode (no regex)
sd -s 'https://old-url.com' 'https://new-url.com' config.yaml

# Pipe from find
find . -name '*.json' | xargs sd '"debug": true' '"debug": false'

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Common pitfalls

• sd uses Perl-like regex by default, not POSIX. If you are porting a sed command, capture groups use $1 not \1 in the replacement string.
• The -s flag switches to literal string matching. Without it, characters like . and * are treated as regex metacharacters, which can cause unexpected matches.
• sd does not support sed's multi-line addressing, delete commands, or hold space. For complex stream editing beyond find-and-replace, sed or awk is still needed.