terminal: Create module to consolidate term utils

Terminal application, a variety of shell configurations, terminal file
and session management all consolidated in one place.

terminal/.config/vifm/scripts/README

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+This directory is dedicated for user-supplied scripts/executables.
+vifm modifies its PATH environment variable to let user run those
+scripts without specifying full path.  All subdirectories are added
+as well.  File in a subdirectory overrules file with the same name
+in parent directories.  Restart might be needed to recognize files
+in newly created or renamed subdirectories.

terminal/.config/vifm/scripts/vifm-default-viewer

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+#!/bin/bash
+
+if [ "$#" -ne 1 ]; then
+    echo "Usage: $0 filename"
+    exit 1
+fi
+
+# upper limit of lines to display for text files
+nlines=250
+# upper limit of bytes to display for binary files
+nbytes=2048
+# language of text files
+language=russian
+# output encoding for text files
+encoding=utf-8
+
+info=$(head -$nlines "$1" | file --mime -)
+charset=${info#*=}
+
+# shellcheck disable=2268
+if [ "x$charset" == "xbinary" ]; then
+    hexdump -e '"%08_ax: "' -e '8/1 "%02x " "  " 8/1 "%02x "' -e '" |" 16/1 "%_p"' -e '"\n"' -v -n $nbytes "$1"
+else
+    head -$nlines "$1" | enconv -g -L $language -x $encoding
+fi

terminal/.config/vifm/scripts/vifm-sixel

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+#!/bin/sh
+
+[ -d "$HOME/.cache/vifm" ] || mkdir -p "$HOME/.cache/vifm"
+
+# $1 action
+action="$1"
+# $2 panel width
+panel_width=$(($2 * 6))
+# $3 panel height
+panel_height=$(($3 * 14))
+# $4 image path
+image_file="$4"
+
+PCACHE="$HOME/.cache/vifm/thumbnail.$(stat --printf '%n\0%i\0%F\0%s\0%W\0%Y' -- "$(readlink -f "$PWD/$image_file")" | sha256sum | awk '{print $1}')"
+
+cleanup() {
+    printf '\33[s\33[5A\33[2K\33[u'
+    clear
+    exit 0
+}
+
+# recieves image with height
+image() {
+    montage "$1" -geometry "${2}x${3}" sixel:-
+}
+
+case "$action" in
+"clear")
+    cleanup
+    ;;
+"draw")
+    [ ! -f "${PCACHE}.jpg" ] && convert "$image_file"'[0]' "${PCACHE}.jpg"
+    # FILE="$PWD/$image_file"
+    image "${PCACHE}.jpg" "$panel_width" "$panel_height"
+    ;;
+"video")
+    [ ! -f "${PCACHE}.jpg" ] &&
+        ffmpegthumbnailer -i "$4" -o "${PCACHE}.jpg" -s 0 -q 5
+    image "${PCACHE}.jpg" "$panel_width" "$panel_height"
+    ;;
+"epub")
+    [ ! -f "${PCACHE}.jpg" ] &&
+        epub-thumbnailer "$image_file" "$PCACHE" 1024
+    image "${PCACHE}.jpg" "$panel_width" "$panel_height"
+    ;;
+"pdf")
+    [ ! -f "${PCACHE}.jpg" ] &&
+        pdftoppm -jpeg -f 1 -singlefile "$image_file" "$PCACHE"
+    image "${PCACHE}.jpg" "$panel_width" "$panel_height"
+    ;;
+"audio")
+    [ ! -f "${PCACHE}.jpg" ] &&
+        ffmpeg -i "$image_file" "${PCACHE}.jpg" -y >/dev/null
+    image "${PCACHE}.jpg" "$panel_width" "$panel_height"
+    ;;
+"font")
+    [ ! -f "${PCACHE}.jpg" ] &&
+        fontpreview -i "$image_file" -o "${PCACHE}.jpg"
+    image "${PCACHE}.jpg" "$panel_width" "$panel_height"
+    ;;
+*) ;;
+esac

terminal/.config/vifm/scripts/vifm-thumbnailer

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+#!/usr/bin/env bash
+
+show_help() {
+    printf """
+vifm-thumbnailer
+
+Easily show images/thumbnails from the vifm file manager.
+
+Usage:  vifm-thumbnailer <current file>
+
+Point it to a file whose directory you want thumbnailed.
+If you point it to a directory itself, it will list its contents.
+
+Options:
+
+    -h      Display this help.
+
+    -r      Show images recursively from current folder.
+
+    -t      Open viewer in thumbnail mode.
+
+    -m      Show thumbnails for video files in addition to image files.
+            Will take longer to load up and requires ffmpeg utilities.
+
+Vifm:
+
+    If the file is on your path (e.g. in ~/.vifm/scripts) from within
+    vifm you can run the script by invoking it with:
+    \`:!vifm-thumbnailer \%%c\`
+    which will show all directory thumbnails with the current file
+    initially shown.
+
+    If you want to have vifm show a filtered view for selected files
+    afterwards add a \%%u to the command.
+
+"""
+}
+
+TMPDIR="$(mktemp -d)"
+valid_files_tmp="$TMPDIR/nsxiv_rifle_$$"
+
+# get all files in directory
+list_img_files() {
+    if exist fd; then
+        fd --max-depth="$maxdepth" -tf . "${1%/*}" | is_img_extension | sort | tee -a "$valid_files_tmp"
+    else
+        find -L "${1%/*}" -maxdepth "$maxdepth" -type f -print | is_img_extension | sort | tee -a "$valid_files_tmp"
+    fi
+}
+
+list_vid_files() {
+    # shellcheck disable=2016
+    find "${1%/*}" -mindepth 1 -maxdepth "$maxdepth" \( -type f -o -type l \) -printf "%P\0" |
+        xargs -r0 -n 20 -P 64 file -00 -L --mime-type -- |
+        xargs -r0 -n 2 sh -c '
+            case "$2" in
+                video/*) printf "%s\0" "$1";;
+            esac
+        ' -- |
+        sort -z |
+        xargs -r0 -I FILE ffmpegthumbnailer -i FILE -o "$TMPDIR/FILE.jpg" -m -s 384
+    find -L "$TMPDIR/" -maxdepth "$maxdepth" -type f -print | sort | tee -a "$valid_files_tmp"
+}
+
+img_ext="jpe?g|png|gif|svg|webp|tiff|heif|avif|ico|bmp"
+is_img_extension() {
+    grep -iE "\.($img_ext)$"
+}
+
+# TODO if marking video thumbnail - will use wrong temporary path on output, makes e.g. vifm %u not work
+open() {
+    trap 'rm -rf -- $TMPDIR' TERM INT EXIT
+    current="$(list_img_files "$1" | grep -nF "$1")"
+    if [ "$videos" = true ]; then
+        list_vid_files "$1"
+    fi
+    [ "$thumbnails" = true ] && nsxiv_args="-t"
+    if [ -n "$current" ]; then
+        nsxiv "$nsxiv_args" -i -n "${current%%:*}" -o -- <"$valid_files_tmp"
+    else
+        # fallback incase file didn't have a valid extension, or we couldn't
+        # find it inside the list
+        nsxiv -o -i -- <"$valid_files_tmp"
+    fi
+}
+
+maxdepth=1
+while getopts "mrt?h" opt; do
+    case "$opt" in
+    r)
+        maxdepth=100
+        ;;
+    m)
+        videos=true
+        ;;
+    t)
+        thumbnails=true
+        ;;
+    h | \? | *)
+        show_help
+        exit 0
+        ;;
+    esac
+done
+shift $((OPTIND - 1))
+[ "$1" = '--' ] && shift
+case "$1" in
+"")
+    echo "Usage: ${0##*/} PICTURES" >&2
+    exit 1
+    ;;
+/*) open "$1" ;;
+"~"/*) open "$HOME/${1#"~"/}" ;;
+*) open "$PWD/$1" ;;
+esac