sd - s[earch] & d[isplace]

sd is an intuitive find & replace CLI.

The Pitch

Why use it over any existing tools?

Painless regular expressions

sd uses regex syntax that you already know from JavaScript and Python. Forget about dealing with quirks of sed or awk - get productive immediately.

String-literal mode

Non-regex find & replace. No more backslashes or remembering which characters are special and need to be escaped.

Easy to read, easy to write

Find & replace expressions are split up, which makes them easy to read and write. No more messing with unclosed and escaped slashes.

Comparison to sed

While sed does a whole lot more, sd focuses on doing just one thing and doing it well.

Some cherry-picked examples, where sd shines:

• Simpler syntax for replacing all occurrences:
  • sd: sd before after
  • sed: sed s/before/after/g
• Replace newlines with commas:
  • sd: sd '\r' ','
  • sed: sed ':a;N;$!ba;s/\r/,/g', or use a different tool like tr.
• Familiar regex syntax by default:
  • sd: echo "start middle end" | sd 'start (.+) end' '$1'
  • sed: basic REs have an unfamiliar and limited syntax, -E for more familiar syntax of extended regular expressions is widely supported but not available on some platforms like Solaris:
    • echo "start middle end" | sed 's/start \(..*\) end/\1/g'
    • echo "start middle end" | sed -E 's/start (.+) end/\1/g'
• Extracting stuff out of strings containing slashes:
  • sd: echo "sample with /path/" | sd '.*(/.*/)' '$1'
  • sed: you need to know that the delimiters for s can be replaced with other arbitrary characters
    • echo "sample with /path/" | sed -E 's|.*(/.*/)|\1|g'
• In place modification of files:
  • sd: sd before after -i file.txt
  • sed: you need to be careful to use -e or else some platforms will consider the next argument to be a backup suffix
    • sed -i -e 's/before/after/g' file.txt

Installation

Cargo

cargo install sd

OS Packages

• Arch linux: There's an AUR package for sd.

Quick Guide

1. String-literal mode. By default, expressions are treated as regex. Use -s or --string-mode to disable regex.

> echo 'lots((([]))) of special chars' | sd -s '((([])))' ''
lots of special chars

2. Basic regex use - let's trim some trailing whitespace

> echo 'lorem ipsum 23   ' | sd '\s+$' ''
lorem ipsum 23

3. Capture groups

Indexed capture groups:

> echo 'cargo +nightly watch' | sd '(\w+)\s+\+(\w+)\s+(\w+)' 'cmd: $1, channel: $2, subcmd: $3'
cmd: cargo, channel: nightly, subcmd: watch

Named capture groups:

> echo "123.45" | sd '(?P<dollars>\d+)\.(?P<cents>\d+)' '$dollars dollars and $cents cents'
123 dollars and 45 cents

In the unlikely case you stumble upon ambiguities, resolve them by using ${var} instead of $var. Here's an example:

> echo '123.45' | sd '(?P<dollars>\d+)\.(?P<cents>\d+)' '$dollars_dollars and $cents_cents'
 and 
> echo '123.45' | sd '(?P<dollars>\d+)\.(?P<cents>\d+)' '${dollars}_dollars and ${cents}_cents'
123_dollars and 45_cents

4. Find & replace in a file

> sd -i 'window.fetch' 'fetch' http.js

That's it. The file is modified in-place.

To do a dry run:

> sd 'window.fetch' 'fetch' http.js 

5. Find & replace across project

Good ol' unix philosophy to the rescue.

fd -t f --exec sd -i 'from "react"' 'from "preact"' {}

Same, but with backups (consider version control).

for file in $(fd -t f); do
  cp "$file" "$file.bk"
  sd -i 'from "react"' 'from "preact"' "$file"; 
done