Как сделать скриншот / скринлист

#!/bin/bash
MAXTHUMB="${2}"
THUMBSIZE="160x120"
OUTPUT_DIR="/Users/iron/Desktop"
WORK_DIR="/tmp/screnshoots"
/bin/rm -rf "$WORK_DIR"
[ -w $WORK_DIR ] || mkdir -p $WORK_DIR
[ -w $OUTPUT_DIR ] || mkdir -p $OUTPUT_DIR
duration_seconds=`ffmpeg -i "$1" 2>&1 | grep "Duration" | cut -f4 -d" " | cut -f3 -d":" | cut -f1 -d","`
duration_minutes=`ffmpeg -i "$1" 2>&1 | grep "Duration" | cut -f4 -d" " | cut -f2 -d":"`
duration_hours=`ffmpeg -i "$1" 2>&1 | grep "Duration" | cut -f4 -d" " | cut -f1 -d":"`
runTime=`echo "$duration_seconds + 60*$duration_minutes + 3600*$duration_hours" | bc`
size=`ffmpeg -i "$1" 2>&1 | /usr/bin/grep "Video:" | cut -f 3 -d ","`
codec=`ffmpeg -i "$1" 2>&1 |  /usr/bin/grep "Video:" | cut -f 1 -d "," | cut -f 4 -d ":"`
MYFILE=`basename "$1"`
echo "*** You specified an input file of -> " "$1"
echo "*** You specified a working directory of -> " "$WORK_DIR"
echo "*** You specified a output directory of -> " "$OUTPUT_DIR"
FILEBASENAME=${MYFILE%.*}
INTERVAL=`echo "$runTime / $MAXTHUMB" | bc`
for numthumb in `seq 1 ${MAXTHUMB}`;
do
CURR_INTERVAL=`echo "$numthumb * $INTERVAL" | bc`
ffmpeg -ss $CURR_INTERVAL -i "$1" -y -vcodec png -vframes 1 -an -f rawvideo "$WORK_DIR""/""$FILEBASENAME""$numthumb"".png" &>/dev/null
done
echo -e "File: ""$MYFILE""
Codec: ""$codec""
Size: ""$size""
Lenght: "$duration_hours"":""$duration_minutes"":""$duration_seconds"" | \
convert -gravity center -font "/Library/Fonts/Microsoft/Bauhaus 93" -pointsize 16 -background none label:@- \
\( +clone -sparse-color Barycentric '0,%h #9b9b9b' \
\) -compose In -composite \
-virtual-pixel transparent \
\( +clone -background black -shadow 50x2+2+2 \
\) +swap -background none -compose over -layers merge +repage \
text.png
echo "*** I will apply the following label -> " $LABEL
montage -tile 3x -shadow -borderwidth 3 -background white -geometry +1+1 "$WORK_DIR""/""$FILEBASENAME""*.png"  "$WORK_DIR""/""$FILEBASENAME"".png"
mogrify -resize 1280x "$WORK_DIR""/""$FILEBASENAME"".png" "$WORK_DIR""/""$FILEBASENAME"".png"
echo "*** Final screencap image is stored here -> " "$OUTPUT_DIR""/""$FILEBASENAME"".jpg"
convert -splice 0x80 -gravity North -draw 'image over 5,5 0,0 text.png' "$WORK_DIR""/""$FILEBASENAME"".png" "$OUTPUT_DIR""/""$FILEBASENAME"".jpg"
/bin/rm -rf "$WORK_DIR";rm text.png