The Line-based Editor, ed

ed is on almost every Linux machine.

Editing with ed

Editing is done in two modes: command and input. ed is in command mode when it's first started.

• Command mode is similar to vim's command mode. Substitutions can be made:

  ,s/OLD/NEW/g
  

  which replaces all occurences of the string OLD with NEW.
  • The , is equivalent to vim's %.
  • Input mode reads stdin and writes it directly to the buffer.

ed Commands

• q: Exit
• P: Starts the prompt. Sort of like command mode in vim.
  • You can run shell commands from here, prefixing with ! (like vim filters)

All ed commands operate over single lines or a range of lines.

• d: deletes lines
• m: moves lines

To only modify a portion of a single line, you'd need to use a replacement command (s)

ed commands consist of optional line addresses, followed by a single character command, and sometimes additional parameters;

[Line[,Line]]Command[Parameters]

The Lines indicate the line or range of lines to be affected by the command. If fewer addresses are given than the command accepts, then default addresses are used.

Prompt-mode Commands

• r: Reads input into the editor buffer.
• <range>p: Prints the specified range to the terminal
  • ,p (using a comma) is shorthand for "the whole buffer"

Input Commands

Input commands make ed enter input mode. These commands are the main way to add text to a file.

• Input Commands:
  • a: Append
  • i: Insert
  • c: Change

In insert mode, no commands are available.
Stdin is written directly to the buffer.

Exit input mode by entering a single dot . on a line.