Bash讀檔案一次讀一行

如果一行裡面沒有空格，可以用for；要不然就用while。比較下面指令的差別：

• for WORD in `cat /etc/passwd`; do echo $WORD; done
• cat /etc/passwd | while read -r LINE; do echo $LINE; done
   
• for WORD in `cat /etc/hosts`; do echo $WORD; done
• cat /etc/hosts | while read -r LINE; do echo $LINE; done

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