sed: 1: invalid command code (BSD sed) macOS Origin: Platform & cloud OSI layer 7 · Application Last updated 5 Nov 2026

macOS: sed: 1: "file.txt": invalid command code f / extra characters at the end of p command

macOS ships BSD sed, where -i requires a backup-suffix argument, unlike GNU sed on Linux.

Exact message you may see sed: 1: invalid command codesed: 1: "file": invalid command code fsed: extra characters at the end of p commandsed: -i may not be used with stdinsed: RE error: illegal byte sequence
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Seen on: macOS Linux

Meaning

Use sed -i '' 's/a/b/' file on macOS (empty string = no backup) or sed -i.bak ... for both. For scripts that must work on Linux and macOS use perl -pi -e, or install GNU sed (brew install gnu-sed, command gsed).

Common causes

  • GNU-style sed -i 's/a/b/' file on macOS
  • Missing empty suffix argument
  • \n/\t escapes not supported in BSD replacement
  • Script written for Linux
  • -r option (use -E)

⚡ Quick fix

  1. sed -i '' 's/a/b/' file on macOS
  2. Portable: sed -i.bak 's/a/b/' file && rm file.bak
  3. brew install gnu-sed and use gsed

Detailed fix by platform

macOS

  1. sed -i.bak 's/foo/bar/g' file && rm file.bak works on both systems

How to diagnose

  1. OS — macOS (BSD)?
  2. Flag — -i suffix?
  3. Portable — perl or gsed?

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: Platform & cloud. Errors that are often confused with or caused by this one (click to open):

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