ed

Additional Notes

ed is the original Unix text editor, designed for editing text files line by line. It is a line editor meaning you navigate and edit by specifying line numbers and search patterns rather than using a full-screen interface. It is standardized by POSIX and available on virtually every Unix-like system.

Despite its minimal interface, ed is powerful for scripting and automated editing. It can be driven by redirecting commands from a file or pipe, making it useful in shell scripts that need to perform simple text transformations. The ed command language influenced later interactive editors like ex, vi, and sed. When run without a filename, ed gives an empty buffer and prints a single ? prompt for errors.

Syntax

ed [options] [file]

Parameters

• file: File to edit. If omitted, ed starts with an empty buffer.

Common Options

• -p prompt: Set the command prompt string. The default is no prompt.
• -s, -q, --quiet: Suppress diagnostics and byte counts. Useful for scripting.
• -G: Enable traditional ed behavior (stricter command parsing).
• -l: Enable more verbose error messages.
• --: Treat remaining arguments as filenames, even if they start with -.

Common Commands

• a: Append text after the current line.
• i: Insert text before the current line.
• c: Change (replace) the current line.
• d: Delete the current line.
• p: Print the current line.
• n: Print the current line with its line number.
• =: Print the current line number.
• l: Print the current line showing non-printing characters.
• r file: Read a file into the buffer after the current line.
• w file: Write the buffer to a file.
• q: Quit.
• Q: Quit without checking for unsaved changes.
• h: Explain the last error.
• H: Enable verbose error explanation mode.
• /pattern/: Search forward for a pattern.
• ?pattern?: Search backward for a pattern.
• s/old/new/: Substitute on the current line.
• +, -: Move forward or backward one line.
• $: Go to the last line.

Examples

ed

Start ed with an empty buffer. Type i, then text, then . on a line by itself to exit insert mode. w filename saves, q quits.

echo -e "1s/foo/bar/\nw\nq" | ed -s file.txt

Replace the first occurrence of foo with bar in file.txt using a scripted ed session.

ed -s file.txt <<< $'1s/old/new/\nw\nq'

Replace old with new on line 1 using a here-string.

ed file.txt

Open file.txt interactively. Commands: 1p prints line 1, $p prints the last line, 1,$l lists all lines, wq saves and quits.

Practical Notes

• ed prints nothing by default on success. A bare ? indicates an error; type h to see the explanation, H to enable verbose errors.
• The . (dot) command on an empty line exits insert mode, not to be confused with the dot command meaning current line.
• For scripting, always use -s to suppress diagnostics and line counts.
• ed reads commands from standard input, so you can pipe an editing script into it.
• GNU ed is the most common Linux implementation. The traditional ed has some behavioral differences.
• If you need screen-based editing, use vi, nano, or a GUI editor instead.