Expand subtitle (srt) range

expandsrtrange.sh

#!/usr/bin/env sh

INFILE="file.srt"
OUTFILE="out-$INFILE"
START=

tac "$INFILE" | while IFS= read -r line; do
    if sub_range="$( echo "$line" | grep " --> " )"; then
        END="$( echo "$sub_range" | cut -d" " -f3 )"

        if [ -n "$START" ]; then
            END="$START,${END##*,}"
        fi

        START="$( echo "$sub_range" | cut -d" " -f1 )"
        echo "$START --> $END"
        START="${START%%,*}"
    else
        echo "$line"
    fi
done | tac > "$OUTFILE" # simpan

# tampilkan hasil
cat "$OUTFILE"