在 linux 的命令行输出进度条

?php
for ($i = 0; $i = 50; $i++) {
printf("progress: [%-50s] %d%%\r", str_repeat('#',$i), $i * 2);
usleep(1000 * 100);
}
echo "\n";
echo "Done.\n";

b=''
for ((i=0;$i=100;i+=2))
do
printf "progress: [%-50s] %d%%\r" $b $i
sleep 0.1
b+='#'
done
echo