plugins/preview-tui

   1 #!/usr/bin/env bash
   2
   3 # Description: Terminal based file previewer
   4 #
   5 # Note: This plugin needs a "NNN_FIFO" to work. See man.
   6 #
   7 # Dependencies:
   8 #   - Supports 6 independent methods to preview with:
   9 #       - tmux (>=3.0), or
  10 #       - kitty with allow_remote_control and listen_on set in kitty.conf, or
  11 #       - wezterm (https://wezfurlong.org/wezterm), or
  12 #       - QuickLook on WSL (https://github.com/QL-Win/QuickLook), or
  13 #       - Windows Terminal (https://github.com/Microsoft/Terminal | https://aka.ms/terminal) with WSL, or
  14 #       - $NNN_TERMINAL set to a terminal (it's xterm by default).
  15 #   - less or $NNN_PAGER
  16 #   - tree or exa/eza or (GNU) ls
  17 #   - mediainfo or file
  18 #   - mktemp
  19 #   - unzip
  20 #   - tar
  21 #   - man
  22 #   - optional: bsdtar or atool for additional archive preview
  23 #   - optional: bat for code syntax highlighting
  24 #   - optional: ueberzug, kitty terminal, wezterm terminal, viu, catimg or chafa for images
  25 #   - optional: convert(ImageMagick) for playing gif preview (required for kitty image previews)
  26 #   - optional: ffmpegthumbnailer for video thumbnails (https://github.com/dirkvdb/ffmpegthumbnailer)
  27 #   - optional: ffmpeg for audio thumbnails
  28 #   - optional: libreoffce for opendocument/officedocument preview
  29 #   - optional: pdftoppm(poppler) for pdf thumbnails
  30 #   - optional: gnome-epub-thumbnailer for epub thumbnails (https://gitlab.gnome.org/GNOME/gnome-epub-thumbnailer)
  31 #   - optional: fontpreview for font preview (https://github.com/sdushantha/fontpreview)
  32 #   - optional: djvulibre for djvu
  33 #   - optional: glow or lowdown for markdown
  34 #   - optional: w3m or lynx or elinks for html
  35 #   - optional: set/export NNN_ICONLOOKUP as 1 to enable file icons in front of directory previews with .iconlookup
  36 #       Icons and colors are configurable in .iconlookup
  37 #   - optional: scope.sh file viewer from ranger.
  38 #       1. drop scope.sh executable in $PATH
  39 #       2. set/export $NNN_SCOPE as 1
  40 #   - optional: pistol file viewer (https://github.com/doronbehar/pistol).
  41 #       1. install pistol
  42 #       2. set/export $NNN_PISTOL as 1
  43 #
  44 # Usage:
  45 #   You need to set a NNN_FIFO path and a key for the plugin with NNN_PLUG,
  46 #   then start `nnn`:
  47 #
  48 #     $ nnn -a
  49 #
  50 #   or
  51 #
  52 #     $ NNN_FIFO=/tmp/nnn.fifo nnn
  53 #
  54 #   Then launch the `preview-tui` plugin in `nnn`.
  55 #
  56 #   If you provide the same NNN_FIFO to all nnn instances, there will be a
  57 #   single common preview window. If you provide different FIFO path (e.g.
  58 #   with -a), they will be independent.
  59 #
  60 #   The previews will be shown in a tmux split. If that isn't possible, it
  61 #   will try to use a kitty terminal split. And as a final fallback, a
  62 #   different terminal window will be used ($NNN_TERMINAL).
  63 #
  64 #   Kitty users need something similar to the following in their kitty.conf:
  65 #   - `allow_remote_control yes`
  66 #   - `listen_on unix:$TMPDIR/kitty`
  67 #   - `enabled_layouts splits` (optional)
  68 #   With ImageMagick installed, this terminal can use the icat kitten to display images.
  69 #   Refer to kitty documentation for further details.
  70 #
  71 #   Wezterm should work out of the box. If `NNN_PREVIEWIMGPROG` is not specified it will use
  72 #   built in iTerm2 image protocol.
  73 #
  74 #   Note that GNU ls is used for its `--group-directories-first` flag.
  75 #   On MacOS this may be installed with `brew install coreutils`, or the flag can be removed.
  76 #   iTerm2 users are recommended to use viu to view images without getting pixelated.
  77 #
  78 #   Windows Terminal users can set "Profile termination behavior" under "Profile > Advanced" settings
  79 #   to automatically close pane on quit when exit code is 0.
  80 #
  81 #   When specifying a different terminal, additional arguments are supported. In particular, you can
  82 #   append a specific title to the terminal and set it to "nofocus" in your WM config.
  83 #   E.g for alacritty and i3, you can set $NNN_TERMINAL to 'alacritty --title preview-tui' and add
  84 #   'no_focus [title="preview-tui"]' to your i3 config file.
  85 #
  86 # Shell: Bash (for environment manipulation through arrays)
  87 # Authors: Todd Yamakawa, Léo Villeveygoux, @Recidiviste, Mario Ortiz Manero, Luuk van Baal, @WanderLanz
  88
  89 NNN_SPLIT=${NNN_SPLIT:-}           # Set permanent split direction
  90 NNN_TERMINAL=${NNN_TERMINAL:-}     # Set external terminal to be used
  91 NNN_SPLITSIZE=${NNN_SPLITSIZE:-50} # Set previewer split size percentage
  92 TMPDIR=${TMPDIR:-/tmp}
  93 NNN_PARENT=${NNN_FIFO#*.}
  94 [ "$NNN_PARENT" -eq "$NNN_PARENT" ] 2>/dev/null || NNN_PARENT="" # Make empty if non-numeric
  95 ENVVARS=(
  96   "PWD=$PWD"
  97   "PATH=$PATH"
  98   "NNN_FIFO=$NNN_FIFO"
  99   "NNN_SCOPE=${NNN_SCOPE:-0}"
 100   "NNN_PISTOL=${NNN_PISTOL:-0}"
 101   "NNN_ICONLOOKUP=${NNN_ICONLOOKUP:-0}"
 102   "NNN_PAGER=${NNN_PAGER:-less -P?n -R -C}"
 103   "NNN_BATTHEME=${NNN_BATTHEME:-ansi}"
 104   "NNN_BATSTYLE=${NNN_BATSTYLE:-numbers}"
 105   "NNN_PREVIEWWIDTH=${NNN_PREVIEWWIDTH:-1920}"
 106   "NNN_PREVIEWHEIGHT=${NNN_PREVIEWHEIGHT:-1080}"
 107   "NNN_PREVIEWDIR=${NNN_PREVIEWDIR:-$TMPDIR/nnn/previews}"
 108   "NNN_PREVIEWIMGPROG=${NNN_PREVIEWIMGPROG:-}"
 109   "FIFOPID=$TMPDIR/nnn-preview-tui-fifopid.$NNN_PARENT"
 110   "FIFOPATH=$TMPDIR/nnn-preview-tui-fifo.$NNN_PARENT"
 111   "PREVIEWPID=$TMPDIR/nnn-preview-tui-previewpid.$NNN_PARENT"
 112   "CURSEL=$TMPDIR/nnn-preview-tui-selection.$NNN_PARENT"
 113   "FIFO_UEBERZUG=$TMPDIR/nnn-preview-tui-ueberzug-fifo.$NNN_PARENT"
 114   "POSOFFSET=$TMPDIR/nnn-preview-tui-posoffset"
 115 )
 116
 117 trap '' PIPE
 118 exists() { type "$1" >/dev/null 2>&1 ;}
 119 pkill() { command pkill "$@" >/dev/null 2>&1 ;}
 120 prompt() { clear; printf "%b" "$@"; cfg=$(stty -g); stty raw -echo; head -c 1; stty "$cfg" ;}
 121 pidkill() {
 122     if [ -f "$1" ]; then
 123         PID="$(cat "$1" 2>/dev/null)" || return 1
 124         kill "$PID" >/dev/null 2>&1
 125         RET=$?
 126         wait "$PID" 2>/dev/null
 127         return $RET
 128     fi
 129     return 1
 130 }
 131
 132 start_preview() {
 133     if [ -e "${TMUX%%,*}" ] && tmux -V | grep -q '[ -][3456789]\.'; then
 134         NNN_TERMINAL=tmux
 135     elif [ -n "$KITTY_LISTEN_ON" ]; then
 136         NNN_TERMINAL=kitty
 137     elif [ -n "$WEZTERM_PANE" ]; then
 138         NNN_TERMINAL=wezterm
 139     elif [ -z "$NNN_TERMINAL" ] && [ "$TERM_PROGRAM" = "iTerm.app" ]; then
 140         NNN_TERMINAL=iterm
 141     elif [ -n "$WT_SESSION" ]; then
 142         NNN_TERMINAL=winterm
 143     else
 144         NNN_TERMINAL="${NNN_TERMINAL:-xterm}"
 145     fi
 146
 147     if [ -z "$NNN_SPLIT" ] && [ $(($(tput lines) * 2)) -gt "$(tput cols)" ]; then
 148         NNN_SPLIT='h'
 149     elif [ "$NNN_SPLIT" != 'h' ]; then
 150         NNN_SPLIT='v'
 151     fi
 152
 153     ENVVARS+=("NNN_TERMINAL=$NNN_TERMINAL" "NNN_SPLIT=$NNN_SPLIT" "QLPATH=$2" "PREVIEW_MODE=1")
 154     case "$NNN_TERMINAL" in
 155         iterm|winterm) # need run in separate shell command: escape
 156             ENVVARS=("${ENVVARS[@]/#/\\\"}")
 157             ENVVARS=("${ENVVARS[@]/%/\\\"}")
 158             command="$SHELL -c 'env ${ENVVARS[*]} \\\"$0\\\" \\\"$1\\\"'" ;;
 159     esac
 160
 161     case "$NNN_TERMINAL" in
 162         tmux) # tmux splits are inverted
 163             ENVVARS=("${ENVVARS[@]/#/-e}")
 164             if [ "$NNN_SPLIT" = "v" ]; then split="h"; else split="v"; fi
 165             tmux split-window "${ENVVARS[@]}" -d"$split" -p"$NNN_SPLITSIZE" "$0" "$1" ;;
 166         kitty) # Setting the layout for the new window. It will be restored after the script ends.
 167             ENVVARS=("${ENVVARS[@]/#/--env=}")
 168             kitty @ goto-layout splits
 169             # Trying to use kitty's integrated window management as the split window.
 170             kitty @ launch --no-response --title "preview-tui" --keep-focus \
 171                 --cwd "$PWD" "${ENVVARS[@]}" --location "${NNN_SPLIT}split" "$0" "$1" ;;
 172         wezterm)
 173             export "${ENVVARS[@]}"
 174             if [ "$NNN_SPLIT" = "v" ]; then split="--horizontal"; else split="--bottom"; fi
 175             wezterm cli split-pane --cwd "$PWD" $split --percent "$NNN_SPLITSIZE" "$0" "$1" >/dev/null
 176             wezterm cli activate-pane-direction Prev ;;
 177         iterm)
 178             if [ "$NNN_SPLIT" = "h" ]; then split="horizontally"; else split="vertically"; fi
 179             osascript <<-EOF
 180             tell application "iTerm"
 181                 tell current session of current window
 182                     split $split with default profile command "$command"
 183                 end tell
 184             end tell
 185 EOF
 186             ;;
 187         winterm)
 188             if [ "$NNN_SPLIT" = "h" ]; then split="H"; else split="V"; fi
 189             wt -w 0 sp -$split -s"0.$NNN_SPLITSIZE" "$command" \; -w 0 mf previous 2>/dev/null ;;
 190         *)  if [ -n "$2" ]; then
 191                 env "${ENVVARS[@]}" QUICKLOOK=1 "$0" "$1" &
 192             else
 193                 # shellcheck disable=SC2086 # (allow arguments)
 194                 env "${ENVVARS[@]}" $NNN_TERMINAL -e "$0" "$1" &
 195             fi ;;
 196     esac
 197 }
 198
 199 toggle_preview() {
 200     export "${ENVVARS[@]}"
 201     if exists QuickLook.exe; then
 202         QLPATH="QuickLook.exe"
 203     elif exists Bridge.exe; then
 204         QLPATH="Bridge.exe"
 205     fi
 206     if pidkill "$FIFOPID"; then
 207         [ -p "$NNN_PPIPE" ] && printf "0" > "$NNN_PPIPE"
 208         pidkill "$PREVIEWPID"
 209         pkill -f "tail --follow $FIFO_UEBERZUG"
 210         if [ -n "$QLPATH" ] && stat "$1"; then
 211             f="$(wslpath -w "$1")" && "$QLPATH" "$f" &
 212         fi
 213     else
 214         [ -p "$NNN_PPIPE" ] && printf "1" > "$NNN_PPIPE"
 215         start_preview "$1" "$QLPATH"
 216     fi
 217 }
 218
 219 fifo_pager() {
 220     cmd="$1"
 221     shift
 222
 223     # We use a FIFO to access $NNN_PAGER PID in jobs control
 224     mkfifo "$FIFOPATH" || return
 225
 226     $NNN_PAGER < "$FIFOPATH" &
 227     printf "%s" "$!" > "$PREVIEWPID"
 228
 229     (
 230         exec > "$FIFOPATH"
 231         if [ "$cmd" = "pager" ]; then
 232             if exists bat; then
 233                 bat --terminal-width="$cols" --decorations=always --color=always \
 234                     --paging=never --style="$NNN_BATSTYLE" --theme="$NNN_BATTHEME" "$@" &
 235             else
 236                 $NNN_PAGER "$@" &
 237             fi
 238         else
 239             "$cmd" "$@" &
 240         fi
 241     )
 242
 243     rm "$FIFOPATH"
 244 }
 245
 246 # Binary file: show file info inside the pager
 247 print_bin_info() {
 248     printf -- "-------- \033[1;31mBinary file\033[0m --------\n"
 249     if exists mediainfo; then
 250         mediainfo "$1"
 251     else
 252         file -b "$1"
 253     fi
 254 }
 255
 256 handle_mime() {
 257     case "$2" in
 258         image/jpeg) image_preview "$cols" "$lines" "$1" ;;
 259         image/gif) generate_preview "$cols" "$lines" "$1" "gif" ;;
 260         image/vnd.djvu) generate_preview "$cols" "$lines" "$1" "djvu" ;;
 261         image/*) generate_preview "$cols" "$lines" "$1" "image" ;;
 262         video/*) generate_preview "$cols" "$lines" "$1" "video" ;;
 263         audio/*) generate_preview "$cols" "$lines" "$1" "audio" ;;
 264         application/font*|application/*opentype|font/*) generate_preview "$cols" "$lines" "$1" "font" ;;
 265         */*office*|*/*document*|*/*msword|*/*ms-excel) generate_preview "$cols" "$lines" "$1" "office" ;;
 266         application/zip) fifo_pager unzip -l "$1" ;;
 267         text/troff)
 268             if exists man; then
 269                 fifo_pager man -Pcat -l "$1"
 270             else
 271                 fifo_pager pager "$1"
 272             fi ;;
 273         *) handle_ext "$1" "$3" "$4" ;;
 274     esac
 275 }
 276
 277 handle_ext() {
 278     case "$2" in
 279         epub) generate_preview "$cols" "$lines" "$1" "epub" ;;
 280         pdf) generate_preview "$cols" "$lines" "$1" "pdf" ;;
 281         gz|bz2) fifo_pager tar -tvf "$1" ;;
 282         md) if exists glow; then
 283                 fifo_pager glow -s dark "$1"
 284             elif exists lowdown; then
 285                 fifo_pager lowdown -Tterm "$1"
 286             else
 287                 fifo_pager pager "$1"
 288             fi ;;
 289         htm|html|xhtml)
 290             if exists w3m; then
 291                 fifo_pager w3m "$1"
 292             elif exists lynx; then
 293                 fifo_pager lynx "$1"
 294             elif exists elinks; then
 295                 fifo_pager elinks "$1"
 296             else
 297                 fifo_pager pager "$1"
 298             fi ;;
 299         7z|a|ace|alz|arc|arj|bz|cab|cpio|deb|jar|lha|lz|lzh|lzma|lzo\
 300         |rar|rpm|rz|t7z|tar|tbz|tbz2|tgz|tlz|txz|tZ|tzo|war|xpi|xz|Z)
 301             if exists atool; then
 302                 fifo_pager atool -l "$1"
 303             elif exists bsdtar; then
 304                 fifo_pager bsdtar -tvf "$1"
 305             fi ;;
 306         *) if [ "$3" = "bin" ]; then
 307                fifo_pager print_bin_info "$1"
 308            else
 309                fifo_pager pager "$1"
 310            fi ;;
 311     esac
 312 }
 313
 314 preview_file() {
 315     clear
 316     # Trying to use pistol if it's available.
 317     if [ "$NNN_PISTOL" -ne 0 ] && exists pistol; then
 318         fifo_pager pistol "$1"
 319         return
 320     fi
 321
 322     # Trying to use scope.sh if it's available.
 323     if [ "$NNN_SCOPE" -ne 0 ] && exists scope.sh; then
 324         fifo_pager scope.sh "$1" "$cols" "$lines" "$(mktemp -d)" "True"
 325         return
 326     fi
 327
 328     # Use QuickLook if it's available.
 329     if [ -n "$QUICKLOOK" ]; then
 330         stat "$1" && f="$(wslpath -w "$1")" && "$QLPATH" "$f" &
 331         return
 332     fi
 333
 334     # Detecting the exact type of the file: the encoding, mime type, and extension in lowercase.
 335     encoding="$(file -bL --mime-encoding -- "$1")"
 336     mimetype="$(file -bL --mime-type -- "$1")"
 337     ext="${1##*.}"
 338     [ -n "$ext" ] && ext="$(printf "%s" "${ext}" | tr '[:upper:]' '[:lower:]')"
 339     lines=$(tput lines)
 340     cols=$(tput cols)
 341
 342     # Otherwise, falling back to the defaults.
 343     if [ -d "$1" ]; then
 344         cd "$1" || return
 345         if [ "$NNN_ICONLOOKUP" -ne 0 ] && [ -f "$(dirname "$0")"/.iconlookup ]; then
 346             [ "$NNN_SPLIT" = v ] && BSTR="\n"
 347             # shellcheck disable=SC2012
 348             ls -F --group-directories-first | head -n "$((lines - 3))" | "$(dirname "$0")"/.iconlookup -l "$cols" -B "$BSTR" -b " "
 349         elif exists tree; then
 350             fifo_pager tree --filelimit "$(find . -maxdepth 1 | wc -l)" -L 3 -C -F --dirsfirst --noreport
 351         elif exists exa; then
 352             exa -G --group-directories-first --colour=always
 353         elif exists eza; then # eza is a community fork of exa (exa is unmaintained)
 354             eza -G --group-directories-first --colour=always
 355         else
 356             fifo_pager ls -F --group-directories-first --color=always
 357         fi
 358         cd ..
 359     elif [ "${encoding#*)}" = "binary" ]; then
 360         handle_mime "$1" "$mimetype" "$ext" "bin"
 361     else
 362         handle_mime "$1" "$mimetype" "$ext"
 363     fi
 364 }
 365
 366 generate_preview() {
 367   if [ -n "$QLPATH" ] && stat "$3"; then
 368         f="$(wslpath -w "$3")" && "$QLPATH" "$f" &
 369   elif [ ! -f "$NNN_PREVIEWDIR/$3.jpg" ] || [ -n "$(find -L "$3" -newer "$NNN_PREVIEWDIR/$3.jpg")" ]; then
 370         mkdir -p "$NNN_PREVIEWDIR/${3%/*}"
 371         case $4 in
 372             audio) ffmpeg -i "$3" -filter_complex "scale=iw*min(1\,min($NNN_PREVIEWWIDTH/iw\,ih)):-1" "$NNN_PREVIEWDIR/$3.jpg" -y ;;
 373             epub) gnome-epub-thumbnailer "$3" "$NNN_PREVIEWDIR/$3.jpg" ;;
 374             font) fontpreview -i "$3" -o "$NNN_PREVIEWDIR/$3.jpg" ;;
 375             gif) if [ -p "$FIFO_UEBERZUG" ] && exists convert; then
 376                     frameprefix="$NNN_PREVIEWDIR/$3/${3##*/}"
 377                     if [ ! -d "$NNN_PREVIEWDIR/$3" ]; then
 378                         mkdir -p "$NNN_PREVIEWDIR/$3"
 379                         convert -coalesce -resize "$NNN_PREVIEWWIDTH"x"$NNN_PREVIEWHEIGHT"\> "$3" "$frameprefix.jpg" ||
 380                         MAGICK_TMPDIR="/tmp" convert -coalesce -resize "$NNN_PREVIEWWIDTH"x"$NNN_PREVIEWHEIGHT"\> "$3" "$frameprefix.jpg"
 381                     fi
 382                     frames=$(($(find "$NNN_PREVIEWDIR/$3" | wc -l) - 2))
 383                     [ $frames -lt 0 ] && return
 384                     while true; do
 385                         for i in $(seq 0 $frames); do
 386                             image_preview "$1" "$2" "$frameprefix-$i.jpg"
 387                             sleep 0.1
 388                         done
 389                     done &
 390                     printf "%s" "$!" > "$PREVIEWPID"
 391                     return
 392                  else
 393                     image_preview "$1" "$2" "$3"
 394                     return
 395                  fi ;;
 396             image) if exists convert; then
 397                        convert "$3" -flatten -resize "$NNN_PREVIEWWIDTH"x"$NNN_PREVIEWHEIGHT"\> "$NNN_PREVIEWDIR/$3.jpg"
 398                    else
 399                        image_preview "$1" "$2" "$3" && return
 400                    fi ;;
 401             office) libreoffice --convert-to jpg "$3" --outdir "$NNN_PREVIEWDIR/${3%/*}"
 402                     filename="$(printf "%s" "${3##*/}" | cut -d. -f1)"
 403                     mv "$NNN_PREVIEWDIR/${3%/*}/$filename.jpg" "$NNN_PREVIEWDIR/$3.jpg" ;;
 404             pdf) pdftoppm -jpeg -f 1 -singlefile "$3" "$NNN_PREVIEWDIR/$3" ;;
 405             djvu) ddjvu -format=ppm -page=1 "$3" "$NNN_PREVIEWDIR/$3.jpg" ;;
 406             video) ffmpegthumbnailer -m -s0 -i "$3" -o "$NNN_PREVIEWDIR/$3.jpg" || rm "$NNN_PREVIEWDIR/$3.jpg" ;;
 407         esac
 408     fi
 409     if [ -f "$NNN_PREVIEWDIR/$3.jpg" ]; then
 410         image_preview "$1" "$2" "$NNN_PREVIEWDIR/$3.jpg"
 411     else
 412         fifo_pager print_bin_info "$3"
 413     fi
 414 } >/dev/null 2>&1
 415
 416 image_preview() {
 417     clear
 418     exec >/dev/tty
 419     if [ "$NNN_TERMINAL" = "kitty" ] && [ -z "$NNN_PREVIEWIMGPROG" ]; then
 420         kitty +kitten icat --silent --scale-up --place "$1"x"$2"@0x0 --transfer-mode=stream --stdin=no "$3" &
 421     elif [ "$NNN_TERMINAL" = "wezterm" ] && [ -z "$NNN_PREVIEWIMGPROG" ]; then
 422         wezterm imgcat "$3" &
 423     elif exists ueberzug && { [ -z "$NNN_PREVIEWIMGPROG" ] || [ "$NNN_PREVIEWIMGPROG" = "ueberzug" ] ;}; then
 424         ueberzug_layer "$1" "$2" "$3" && return
 425     elif exists catimg   && { [ -z "$NNN_PREVIEWIMGPROG" ] || [ "$NNN_PREVIEWIMGPROG" = "catimg" ] ;}; then
 426         catimg "$3" &
 427     elif exists viu      && { [ -z "$NNN_PREVIEWIMGPROG" ] || [ "$NNN_PREVIEWIMGPROG" = "viu" ] ;}; then
 428         viu -t "$3" &
 429     elif exists chafa    && { [ -z "$NNN_PREVIEWIMGPROG" ] || [ "$NNN_PREVIEWIMGPROG" = "chafa" ] ;}; then
 430         chafa "$3" &
 431     else
 432         fifo_pager print_bin_info "$3" && return
 433     fi
 434     printf "%s" "$!" > "$PREVIEWPID"
 435 }
 436
 437 ueberzug_layer() {
 438     [ -f "$POSOFFSET" ] && read -r x y < "$POSOFFSET"
 439     printf '{"action": "add", "identifier": "nnn_ueberzug", "x": %d, "y": %d, "width": "%d", "height": "%d", "scaler": "fit_contain", "path": "%s"}\n'\
 440         "${x:-0}" "${y:-0}" "$1" "$2" "$3" > "$FIFO_UEBERZUG"
 441 }
 442
 443 ueberzug_remove() {
 444     printf '{"action": "remove", "identifier": "nnn_ueberzug"}\n' > "$FIFO_UEBERZUG"
 445 }
 446
 447 winch_handler() {
 448     clear
 449     pidkill "$PREVIEWPID"
 450     if [ -p "$FIFO_UEBERZUG" ]; then
 451         pkill -f "tail --follow $FIFO_UEBERZUG"
 452         tail --follow "$FIFO_UEBERZUG" | ueberzug layer --silent --parser json &
 453     fi
 454     preview_file "$(cat "$CURSEL")"
 455 }
 456
 457 preview_fifo() {
 458     while read -r selection; do
 459         if [ -n "$selection" ]; then
 460             pidkill "$PREVIEWPID"
 461             [ -p "$FIFO_UEBERZUG" ] && ueberzug_remove
 462             [ "$selection" = "close" ] && break
 463             preview_file "$selection"
 464             printf "%s" "$selection" > "$CURSEL"
 465         fi
 466     done < "$NNN_FIFO"
 467     sleep 0.1 # make sure potential preview by winch_handler is killed
 468     pkill -P "$$"
 469 }
 470
 471 if [ "$PREVIEW_MODE" -eq 1 ] 2>/dev/null; then
 472     if [ "$NNN_TERMINAL" != "kitty" ] && exists ueberzug; then
 473         mkfifo "$FIFO_UEBERZUG"
 474         tail --follow "$FIFO_UEBERZUG" | ueberzug layer --silent --parser json &
 475     fi
 476
 477     preview_file "$PWD/$1"
 478     preview_fifo &
 479     printf "%s" "$!" > "$FIFOPID"
 480     printf "%s" "$PWD/$1" > "$CURSEL"
 481     trap 'winch_handler; wait' WINCH
 482     trap 'rm "$PREVIEWPID" "$CURSEL" "$FIFO_UEBERZUG" "$FIFOPID" "$POSOFFSET" 2>/dev/null' INT HUP EXIT
 483     wait "$!" 2>/dev/null
 484     exit 0
 485 else
 486     if [ ! -r "$NNN_FIFO" ]; then
 487         prompt "No FIFO available! (\$NNN_FIFO='$NNN_FIFO')\nPlease read Usage in '$0'."
 488     elif [ "$KITTY_WINDOW_ID" ] && [ -z "$TMUX" ] && [ -z "$KITTY_LISTEN_ON" ]; then
 489         prompt "\$KITTY_LISTEN_ON not set!\nPlease read Usage in '$0'."
 490     else
 491         toggle_preview "$1" &
 492     fi
 493 fi