在处理文件时遇到个问题,当文件名包含空格时,for循环就出问题了。
例如,我在当前文件夹下建立3个文件名包含空格的文件:
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循环输出文件名:
keakons-MacBook-Pro:test keakon$ for file in `ls`; > do echo $file; > done test 1 test 2 test 3
可以看到,文件名被分开了。
复制操作也不行:www.jbxue.com
keakons-MacBook-Pro:test keakon$ mkdir ../bak keakons-MacBook-Pro:test keakon$ for file in `ls`; do cp "$file" ../bak; done cp: bak is a directory (not copied). cp: test: No such file or directory cp: 1: No such file or directory cp: test: No such file or directory cp: 2: No such file or directory cp: test: No such file or directory cp: 3: No such file or directory
要解决这个问题,当然就要从单词分隔符着手。而bash中使用的是$IFS(Internal Field Separator)这个变量,内容为" \n\t":
keakons-MacBook-Pro:test keakon$ echo $IFS keakons-MacBook-Pro:test keakon$ echo "$IFS" | od -t x1 0000000 20 09 0a 0a 0000004 keakons-MacBook-Pro:test keakon$ echo "" | od -t x1 0000000 0a 0000001
然后把它改成"\n\b",记得修改前先保存一下:
keakons-MacBook-Pro:test keakon$ SAVEIFS=$IFS keakons-MacBook-Pro:test keakon$ IFS=$(echo -en "\n\b")
现在再执行上述命令就正常了:
keakons-MacBook-Pro:test keakon$ 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
最后,别忘了恢复$IFS:
keakons-MacBook-Pro:test keakon$ IFS=$SAVEIFS keakons-MacBook-Pro:test keakon$ echo "$IFS" | od -t x1 0000000 20 09 0a 0a 0000004 keakons-MacBook-Pro:test keakon$ IFS=$(echo -en " \n\t") keakons-MacBook-Pro:test keakon$ echo "$IFS" | od -t x1 0000000 20 0a 09 0a 0000004