zsh style trailing newline in bash

README.md

Trailing Newlines

In zsh, if a command lacks a trailing newline (like echo -n hello), an inverted percent sign with a newline is appended to the output so the prompt can be printed on its own line, not directly after the output. The bashrc in this example will emulate this behavior in bash.

Without fancynewline

dave @ [ manilla :: (Darwin) ] ~ $ echo hello
hello
dave @ [ manilla :: (Darwin) ] ~ $ echo -n hello
hellodave @ [ manilla :: (Darwin) ] ~ $

With fancynewline

dave @ [ manilla :: (Darwin) ] ~ $ echo hello
hello
dave @ [ manilla :: (Darwin) ] ~ $ echo -n hello
hello%
dave @ [ manilla :: (Darwin) ] ~ $

Credits

• #bash on freenode
• http://stackoverflow.com/questions/2575037/how-to-get-the-cursor-position-in-bash

bashrc

# http://stackoverflow.com/questions/2575037/how-to-get-the-cursor-position-in-bash
# print the current column of the cursor
curcol() {
	local pos oldstty row=0 col=0
	exec < /dev/tty
	oldstty=$(stty -g)
	stty raw -echo min 0
	tput u7 > /dev/tty
	IFS=';' read -r -d R -a pos
	stty "$oldstty"
	# change from one-based to zero based so they work with: tput cup $row $col
	col=${pos[1]}
	col=$((${col:-1} - 1))
	echo "$col"
}

# conditonally output `%\n` based on the current column of the cursor
fancynewline() {
	if (( $(curcol) != 0 )); then
		tput bold
		tput rev
		echo '%'
		tput sgr0
	fi
}

PROMPT_COMMAND=fancynewline

This has an issue, if you start typing in a command before the last command has finished, anything typed will be lost.

ie. run sleep 3, and as it's running type ls<enter>. normally, once the sleep has finished ls will be executed, but with this in place, the text ls<enter> will be lost.

this also doesn't seem to work under screen-256color terminfo

In order to make work under screen-256color terminfo (which is what tmux uses), compile the following terminfo with tic https://gist.github.com/4770f748854f37c97fcb and use that with tmux instead (in ~/.tmux.conf set -g default-terminal "screen-256color-new").

(It adds u7 (user string 7) to the terminfos, which xterm has defined, which is used with tput to get the cursor location).

Though I suppose more easily the script could be modified to use echo -en "\033[6n" in lieu of tput u7.