文件按行数分割，且限制文件大小（非完美解决方案）

main.sh

#!/bin/bash
# usage: bash this.sh lines lineBytes file toDir

lines=$1
lineBytes=$2
file=$3
toDir=$4

if [ "Darwin" = "$(uname)" ]; then
    # MacOS: brew install coreutils
    split="gsplit"
else
    split="split"
fi

mkdir -p "$toDir"
$split -l "$lines" "$file" "$toDir/"
cd "$toDir" || exit
for item in *; do
    if [ "$(wc -c <"$item")" -gt "$lineBytes" ]; then
        $split -C "$lineBytes" "$item" "${item}_"
        rm "$item"
    fi
done