ed (the awesome UNIX line editor)

ed is a clone of the UNIX command-line tool by the same name ed a line editor that was nortorious for being and most unfriendly editor ever created.

This is a modern take on that editor writtein in the Go language for portability with all the basic ed commands, a modern readline line editor with vi bindings and friendly error messages when things go wrong.

Some future ideas may include:

• Syntax Highlighting
• Color Prompt
• A pony?!

Quick Start

$ go get github.com/prologic/ed
$ ed

For help on how to use ed in general please refer to this excellent guide:

• Actually using ed

Or the GNU ed manual

NOTE: This port/clone does not implement all ed commands, only a subset.

Example

Here is an example ed session:

$ ed
> a
Start typing a few lines.
Anything you want, really.
Just go right ahead.
When you're done, just type a period by itself.
.
> p
When you're done, just type a period by itself.
> n
4    When you're done, just type a period by itself.
> .n
4    When you're done, just type a period by itself.
> 3
Just go right ahead.
> .n
3    Just go right ahead.
> a
Entering another line.
.
> n
4    Entering another line.
> i
A line before the current line.
.
> n
4    A line before the current line.
> c
I decided I like this line better.
.
> n
4    I decided I like this line better.
>

Commands

This implementation supports the following commands: (not all commands from the original ed are supported nor the GNU ed)

Command	Description	Notes
``	newline	Null command. An address alone prints the addressed line. A alone is equivalent to '+1p'. The current address is set to the address of the printed line.
!shell	exec shell	Executes a shell command with sh(1).
=	print index	Prints the line number of the addressed line. The current address is unchanged.
/ re	search text	The next line containing the regular expression re. The search wraps to the beginning of the buffer and continues down to the current line, if necessary. THe last search can be repeated with / and an empty re.
a	append text	Appends text to the buffer after the addressed line. Text is entered in input mode. The current address is set to the address of the last line entered or, if there were none, to the addressed line.
c	change lines	Changes lines in the buffer. The addressed lines are deleted from the buffer, and text is inserted in their place. Text is entered in input mode. The current address is set to the address of the last line entered or, if there were none, to the new address of the line after the last line deleted; if the lines deleted were originally at the end of the buffer, the current address is set to the address of the new last line; if no lines remain in the buffer, the current address is set to zero.
d	delete lines	Deletes the addressed lines from the buffer. The current address is set to the new address of the line after the last line deleted; if the lines deleted were originally at the end of the buffer, the current address is set to the address of the new last line; if no lines remain in the buffer, the current address is set to zero.
e file	edit file	Edits file, and sets the default filename. If file is not specified, then the default filename is used. Any lines in the buffer are deleted before the new file is read. The current address is set to the address of the last line in the buffer.
f file	set filename	Sets the default filename to file. If file is not specified, then the default unescaped filename is printed.
i	insert text	Inserts text in the buffer before the addressed line. The address '0' (zero) is valid for this command; it places the entered text at the beginning of the buffer. Text is entered in input mode. The current address is set to the address of the last line entered or, if there were none, to the addressed line.
j .	join lines .	Joins the addressed lines, replacing them by a single line containing their joined text. If only one address is given, this command does nothing. If lines are joined, the current address is set to the address of the joined line. Else, the current address is unchanged.
n	numbered	Number command. Prints the addressed lines, preceding each line by its line number and a . The current address is set to the address of the last line printed.
p	print lines	Prints the addressed lines. The current address is set to the address of the last line printed.
q	quit	Quits ed. A warning is printed if any changes have been made in the buffer since the last 'w' command that wrote the entire buffer to a file.
r file	read file	Reads file and appends it after the addressed line. If file is not specified, then the default filename is used. If there is no default filename prior to the command, then the default filename is set to file. Otherwise, the default filename is unchanged. The address '0' (zero) is valid for this command; it reads the file at the beginning of the buffer. The current address is set to the address of the last line read or, if there were none, to the addressed line. If file is prefixed with a bang (!), then it is interpreted as a shell command whose output is to be read, (see shell escape command '!' below). In this case the default filename is unchanged.
w file	write file	Writes the addressed lines to file. Any previous contents of file is lost without warning. If there is no default filename, then the default filename is set to file, otherwise it is unchanged. If no filename is specified, then the default filename is used. The current address is unchanged.
wq file	write & quit	Writes the addressed lines to file, and then executes a 'q' command.
x	put text	Copies (puts) the contents of the cut buffer to after the addressed line. The current address is set to the address of the last line copied.
y	yank text	Copies (yanks) the addressed lines to the cut buffer. The cut buffer is overwritten by subsequent 'c', 'd', 'j', 's', or 'y' commands. The current address is unchanged.

License

`ed` is licensed under the terms of the [MIT License](https://opensource.org/licenses/MIT)