keakons-MacBook-Pro:test keakon$ touch "test 1" keakons-MacBook-Pro:test keakon$ touch "test 2" keakons-MacBook-Pro:test keakon$ touch "test 3" keakons-MacBook-Pro:test keakon$ ls test 1 test 2 test 3
然后for循環輸出文件名：
復制代碼 代碼如下:
keakons-MacBook-Pro:test keakon$ for file in `ls`; > do echo $file; > done test 1 test 2 test 3
可以看到，文件名被分開了。
復制操作也不行：
復制代碼 代碼如下:
keakons-MacBook-Pro:test keakon$ mkdir ../bak keakons-MacBook-Pro:test keakon$ for file in `ls`; do cp "$file" ../bak; done cp: bak is a directory (not copied). cp: test: No such file or directory cp: 1: No such file or directory cp: test: No such file or directory cp: 2: No such file or directory cp: test: No such file or directory cp: 3: No such file or directory
要解決這個問題，當然就要從單詞分隔符著手。而bash中使用的是$IFS（Internal Field Separator）這個變量，內容為" \n\t"：
keakons-MacBook-Pro:test keakon$ for file in `ls`; do echo $file; done test 1 test 2 test 3 keakons-MacBook-Pro:test keakon$ for file in `ls`; do cp "$file" ../bak; done keakons-MacBook-Pro:test keakon$ ls ../bak test 1 test 2 test 3
