問題簡介
$ cat print_status.sh
!/bin/bash
echo "[INFO] Processing file: readme.txt"
sleep 2  To simulate the file processing

echo "[INFO] Processing file: veryPowerfulService.service"
sleep 2

echo "[INFO] Processing file: log.txt"
echo "DONE"


$ ./print_status.sh
[INFO] Processing file: readme.txt
[INFO] Processing file: veryPowerfulService.service
[INFO] Processing file: log.txt
DONE
「魔法碼」: \033[0K\r
  • -n 讓 echo 不輸出結尾的換行字元
  • -e 讓 echo 解讀反斜線逸出字元，例如 \n（換行）與 \r（回車）
  • \033 - 逸出序列，也就是 ESC
  • \033[ - 變成 “ESC ["，也就是控制序列引導字元（CSI）
  • \033[0k - 即 “CSI 0 K”，會清除從游標到行尾的文字
  • \r - 回車，將游標移回行首
$ cat print_status.sh
#!/bin/bash
echo -ne "[INFO] Processing file: readme.txt\033[0K\r"
sleep 2

echo -ne "[INFO] Processing file: veryPowerfulService.service\033[0K\r"
sleep 2

echo -e "[INFO] Processing file: log.txt\033[0K\r"
echo "DONE"

!/bin/bash
printf "[INFO] Processing file: readme.txt\033[0K\r"
sleep 2

printf "[INFO] Processing file: veryPowerfulService.service\033[0K\r"
sleep 2

printf "[INFO] Processing file: log.txt\033[0K\r\n"
echo "DONE"