如果(-f)在perl中怎么办？

发布时间：2020-12-15 21:21:49 所属栏目：大数据来源：网络整理

导读：我遇到这行代码： if( -f filename ) { ... } -f似乎测试文件名是否存在，但我不确定。 Google目前还没有帮助(Google很难为“-f”)，也没有我的Perl图书。任何人都可以咨询？解决方法见 perlfunc。它列出了所有perl内置函数，包括“文件测试”功能： -X

我遇到这行代码：

if( -f <filename> ) { ... }

-f似乎测试文件名是否存在，但我不确定。 Google目前还没有帮助(Google很难为“-f”)，也没有我的Perl图书。

任何人都可以咨询？

解决方法

见 perlfunc。

它列出了所有perl内置函数，包括“文件测试”功能：

-X FILEHANDLE
-X EXPR
-X DIRHANDLE
-X

其中-X是以下之一：

-r: File is readable by effective uid/gid.
-w: File is writable by effective uid/gid.
-x: File is executable by effective uid/gid.
-o: File is owned by effective uid.

-R: File is readable by real uid/gid.
-W: File is writable by real uid/gid.
-X: File is executable by real uid/gid.
-O: File is owned by real uid.

-e: File exists.
-z: File has zero size (is empty).
-s: File has nonzero size (returns size in bytes).

-f: File is a plain file.
-d: File is a directory.
-l: File is a symbolic link.
-p: File is a named pipe (FIFO),or Filehandle is a pipe.
-S: File is a socket.
-b: File is a block special file.
-c: File is a character special file.
-t: Filehandle is opened to a tty.

-u: File has setuid bit set.
-g: File has setgid bit set.
-k: File has sticky bit set.

-T: File is an ASCII text file (heuristic guess).
-B: File is a "binary" file (opposite of -T).

-M: Script start time minus file modification time,in days.
-A: Same for access time.
-C: Same for inode change time (Unix,may differ for other platforms)

（编辑：李大同）

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