Video preview with nnn
Live previews
A live preview is a window that renders or shows information on the hovered entry. As the cursor moves, the live preview window will automatically update.
There are two ways to enable live previews in nnn:
- using a previewer plugin,
- using a custom wrapper/previewer script.
Both use the path in NNN_FIFO to get hover updates.
Previewer plugins
Set up NNN_FIFO
Depends on how many simultaneous nnn instances you need:
-
Single instance: export a global FIFO path in, e.g.,
.profile:export NNN_FIFO=/tmp/nnn.fifo -
Multiple instances: use the option
-ato create a new FIFO path for each instance.
Plugin usage
Follow the instructions in the plugin documentation for installation and general plugin configuration.
There are 2 previewer plugins for nnn, using various mechanisms to display the preview window:
- preview-tabbed: the preview window is a tabbed X window, files are viewed using Xembed capable programs (mpv for audio/video, sxiv for images, zathura for PDF, xterm/urxvt/st + nuke plugin text preview for other files)
- preview-tui: the preview window is either a tmux pane, a new terminal window or a kitty pane (needs kitty's
allow_remote_controloption turned on), and files are previewed using tools like tree, less, file, mediainfo, kitty's icat, ueberzug etc. On WSL it will use QuickLook to preview files. It can also use ranger's scope.sh or pistol. Feel free to submit a pull-request for any previewer you feel is missing.
To run a previewer (or any plugin in general) when you start nnn, use the option -P
Notes:
nnndoes not watch the hovered file and update the path if it's modified while under preview. Press Esc or click on the entry to update the preview without changing the hovered entry.- To close the
preview-tuipreview windows run the plugin again or press ^C on the preview window.
Custom script configuration example
There are two aspects to creating a live preview:
- A preview command
- A setup command
Preview command example
#!/usr/bin/env sh
# #############################################################################
# File: preview_cmd.sh
# Description: Minimal example to preview files and directories
# No external dependencies
# Can be easily extended
# Automatically exits when the NNN_FIFO closes
# Prints a `tree` if directory or `head` if it's a file
#
# Shell: POSIX compliant
# Author: Todd Yamakawa
#
# ToDo:
# 1. Add support for more types of files
# e.g. binary files, we shouldn't try to `head` those
# #############################################################################
# Check FIFO
NNN_FIFO=${NNN_FIFO:-$1}
if [ ! -r "$NNN_FIFO" ]; then
echo "Unable to open \$NNN_FIFO='$NNN_FIFO'" | less
exit 2
fi
# Read selection from $NNN_FIFO
while read -r selection; do
clear
lines=$(($(tput lines)-1))
cols=$(tput cols)
# Print directory tree
if [ -d "$selection" ]; then
cd "$selection" || continue
tree | head -n $lines | cut -c 1-"$cols"
continue
fi
# Print file head
if [ -f "$selection" ]; then
head -n $lines "$selection" | cut -c 1-"$cols"
continue
fi
# Something went wrong
echo "Unknown type: '$selection'"
done < "$NNN_FIFO"
Setup command example
To create your own setup command, you need the following steps:
- Create a
NNN_FIFO - Run your preview command in the background
- Run
nnn - Delete your
NNN_FIFO
Here is am example bash/zsh function. To use this example, you will need to set the preview command.
For the preview window:
- It uses
tmuxsplit if you're currently running in atmuxenvironmenttmux 3.0is required for setting environment variables in a new pane
- Otherwise it uses an
xtermwindow
nnn-preview ()
{
# Block nesting of nnn in subshells
if [ -n "$NNNLVL" ] && [ "${NNNLVL:-0}" -ge 1 ]; then
echo "nnn is already running"
return
fi
# The default behaviour is to cd on quit (nnn checks if NNN_TMPFILE is set)
# If NNN_TMPFILE is set to a custom path, it must be exported for nnn to see.
# To cd on quit only on ^G, remove the "export" and set NNN_TMPFILE *exactly* as this:
# NNN_TMPFILE="${XDG_CONFIG_HOME:-$HOME/.config}/nnn/.lastd"
export NNN_TMPFILE="${XDG_CONFIG_HOME:-$HOME/.config}/nnn/.lastd"
# This will create a fifo where all nnn selections will be written to
NNN_FIFO="$(mktemp --suffix=-nnn -u)"
export NNN_FIFO
(umask 077; mkfifo "$NNN_FIFO")
# Preview command
preview_cmd="/path/to/preview_cmd.sh"
# Use `tmux` split as preview
if [ -e "${TMUX%%,*}" ]; then
tmux split-window -e "NNN_FIFO=$NNN_FIFO" -dh "$preview_cmd"
# Use `xterm` as a preview window
elif (which xterm &> /dev/null); then
xterm -e "$preview_cmd" &
# Unable to find a program to use as a preview window
else
echo "unable to open preview, please install tmux or xterm"
fi
nnn "$@"
rm -f "$NNN_FIFO"
}