make-xz - simple frontend for tar & xz

#!/bin/sh
# make-xz v1.11 - simple frontend for tar & xz with a nice progress bar. Usage: make-xz.sh [path to source file or dir] [path to target file]
# Source path must lead to a file or directory. It then decides whether to use tar in addition or not. If no target is given the source path is
# used for the archive. The xz or tar.xz suffixes will be added automatically if not present in the target file name. Use the $COMPRESS variable
# to set compression method and strength. You may use presets from 0 to 9 and add "e" for a more extreme compression or use custom options.

. progress.sh

ERROR(){
        printf "\033[0;31mError - $1\033[0;32m\n"
        exit 1
}

[ -z "$1" ] || [ ! -e "$1" ] && ERROR "Wrong input path or file name or none at all."

LOG=/media/ramdisk/log_$(date +%y%m%d%H%M%S%3N)
PROGRESS_MAX1=$(($(du -s -- "$1" | cut -f1)/102))
PROGRESS_MAX2=1000
PROGRESS_R1=" "
PROGRESS_FT=T
PROGRESS_MSG=" Compressed file size compared to original: "
#COMPRESS=" --lzma2=dict=256MiB,lc=0,lp=0,pb=2,mode=normal,nice=273,mf=bt4,depth=512"
COMPRESS=9e
export XZ_DEFAULTS="-T0 -vvcz$COMPRESS"

[ -d "$1" ] && SUFFIX=.tar.xz || SUFFIX=.xz
if [ -z "$2" ]; then
    OUT=$(printf "$1" | sed 's:/*$::')$SUFFIX    # remove all trailing slashes & add suffix
else
    FILENAME=${2%*$SUFFIX}
    [ -z ${2#$FILENAME*} ] && OUT="$2"$SUFFIX || OUT="$2"
fi
if [ -e "$OUT" ]; then
    read -r -p "Output file already exists. Overwrite (y/N)? " OPT
    case $OPT in
        y|Y)
            rm -f "$OUT"
            ;;
        *)
            ERROR "Error: Unable to write output file."
            ;;
    esac
fi
printf "Compressing file"
# XZ triggers a SIGALRM every second as an indicator to print its progress output to stdout.
# However, by redirecting XZ's progress output the SIGALRM is no longer sent preventing XZ from emitting any progress info.
# With the following code the SIGALRM is sent "manually" making XZ print its progress again and wherever we want.
{
    if [ $SUFFIX = .xz ]; then
        echo " with XZ..."
        xz "$1" > "$OUT" & XZ_PID=$!
    else
        echo "s with TAR-XZ..."
        tar -JC "$1/.." "$(basename "$1")" -cf "$OUT" &
        while [ -z $XZ_PID ]; do    # wait for XZ's PID to appear in the process list
            sleep 0.2s
            XZ_PID=$(ps -e | grep ' xz' | awk -F' ' '{$1=$1;print $1}')
        done
    fi
    while sleep 0.2s; do
        kill -ALRM "$XZ_PID" || break
    done
    wait "$XZ_PID"
} 2>$LOG &
while ! grep -qs "MiB = " $LOG; do sleep 0.2s; done    # wait for XZ to stream it's output
while [ -n "$(ps -e | grep ' xz')" ]; do
    # The long SED filter chain at the end strips the output down to a clean number by removing all leading zeros
    # and any other unwanted junk while preserving the value if it's just zero.
    PROG=$(tail -n1 $LOG | cut -d"/" -f2 | awk -F 'MiB = ' '{print $1}' | sed 's/[^0-9]*//g;s/^0*\([1-9]\)/\1/;s/^0*$/0/')
    RATIO=$(tail -n1 $LOG | cut -d"=" -f2 | awk -F ' ' '{print $1}' | sed 's/[^0-9]*//g;s/^0*\([1-9]\)/\1/;s/^0*$/0/')
    PROGRESS_BAR $PROG $RATIO
    sleep 0.1s
done
PROGRESS_BAR $PROGRESS_MAX1 $RATIO
rm -f $LOG
printf "\033[4B\n"