.lessfilter for various input files (code highlighting, image and binary files display, …).

.lessfilter

#!/bin/bash -x
# input preprocessor for less

function cmdexist() {
  which "$1" >/dev/null
}

function colorize() {
  if which pygmentize >/dev/null ; then
    pygmentize -g "$1"
  fi
}

# Check usage
if [ $# -gt 1 ]; then
    echo "Usage: Don't use it directly"
    echo 'Launch "eval $(/path/to/lesspipe.sh)" to use it with less'
fi

# We just determine file type of $1
# and determine which viewer is appropriate
case "$(file -Lb "$1")" in
# Image
*image[[:space:]]data*)
    width=$(stty size | cut -d ' ' -f 2)
    if cmdexist termpix; then
        # https://github.com/hopey-dishwasher/termpix
        termpix "$1" --width $width --true-color
    elif cmdexist terminal-image-viewer; then
        # Wrapper around this https://github.com/stefanhaustein/TerminalImageViewer.git
        terminal-image-viewer -w $width "$1"
    elif cmdexist img2txt; then
        # libcaca (caca-utils package)
        img2txt -W $width -f utf8 "$1"
    fi
    ;;
# Archive
POSIX[[:space:]]tar[[:space:]]archive*)
    tar tvvf "$1" ;;
gzip[[:space:]]compressed[[:space:]]data*) # Test if tar or man
    if gzip -dc "$1" | file - | grep -q 'tar archive' ; then
        tar tvvf "$1"
    elif gzip -dc "$1" | file - | grep -q 'roff' ; then
        gzip -dc "$1" | nroff -S -mandoc -
    else
        gzip -dc "$1"
    fi ;;
bzip2[[:space:]]compressed[[:space:]]data*)
    if bzip2 -dc "$1" | file - | grep -q 'tar archive' ; then
        tar tvvf "$1"
    elif bzip2 -dc "$1" | file - | grep -q 'roff' ; then
        bzip2 -dc "$1" | nroff -S -mandoc -
    else
        bzip2 -dc "$1"
    fi ;;
cpio[[:space:]]archive)
    cmdexist cpio && cpio -it < "$1" ;;
[Xx][Zz][[:space:]]compressed[[:space:]]data*)
    if xz -dc "$1" | file - | grep 'tar archive' ; then
        xz -dc "$1" | tar tvvf -
    else
        xz -dc "$1"
    fi ;;
data) # Test if lzma archive
    if xz -t "$1" ; then
        if xz -F lzma -dc "$1" | file - | grep 'tar archive' ; then
            xz -F lzma -dc "$1" | tar tvvf -
        else
            xz -F lzma -dc "$1"
        fi
    else
        echo "Unrecognized file"
    fi ;;
ISO[[:space:]]9660[[:space:]]CD-ROM[[:space:]]filesystem[[:space:]]data*)
    if cmdexist isoinfo ; then
        echo "$1:" ; isoinfo -d -i "$1"
        echo
        echo '***Contents:' ; isoinfo -f -i "$1"
    fi ;;
Zip[[:space:]]archive[[:space:]]data*)
    unzip -l "$1" ;;
RAR[[:space:]]archive[[:space:]]data*)
    cmdexist unrar && unrar l "$1" ;;

# Distributions Packages
Debian[[:space:]]binary[[:space:]]package*)
    if cmdexist dpkg ; then
        echo "$1:" ; dpkg --info "$1"
        echo
        echo '*** Contents:' ; dpkg-deb --contents "$1"
    else
        ar p "$1" data.tar.gz | tar tzvf -
    fi ;;
RPM*)
    if cmdexist rpm ; then
        echo "$1:" ; rpm -q -i -p "$1"
        echo
        echo '*** Contents:' ; rpm -q -l -p "$1"
    elif cmdexist rpm2cpio ; then
        rpm2cpio "$1" | cpio -it
    elif cmdexist rpm2tar ; then
        rpm2tar -O "$1" | tar tvf -
    fi ;;

# text
*text*|HTML*)
    if [[ "$1" =~ [.]*md$ ]] ; then
        mdv "$1"
    else
        colorize "$1"
    fi ;;
esac