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Perl 在if语句中-e是什么意思?_Perl - Fatal编程技术网

Perl 在if语句中-e是什么意思?

Perl 在if语句中-e是什么意思?,perl,Perl,我在一些Perl代码中发现了以下内容: if (! -e $options{"inPath"}){ $logger->fatal("Directory \'$options{\"inPath\"}\' does not exist.\n"); } 如果语句中的-e有什么作用?请参见文档站点中的-e'/foo'返回true 如果系统中安装了perldoc,也可以从命令行访问它 perldoc -f -X 请参阅文档站点中的-e'/foo'返回true 如果系统中安装了pe

我在一些Perl代码中发现了以下内容:

if (! -e $options{"inPath"}){
       $logger->fatal("Directory \'$options{\"inPath\"}\' does not exist.\n");
} 
如果
语句中的
-e
有什么作用?

请参见文档站点中的<如果文件
/foo
存在,则code>-e'/foo'
返回true

如果系统中安装了perldoc,也可以从命令行访问它

perldoc -f -X
请参阅文档站点中的<如果文件
/foo
存在,则code>-e'/foo'返回true

如果系统中安装了perldoc,也可以从命令行访问它

perldoc -f -X
一元运算符
-e
检查文件是否存在


Perldoc一元文件测试操作符列表:

    -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 (false if symlinks aren't
        supported by the file system).
    -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 or UTF-8 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)
一元运算符
-e
检查文件是否存在


Perldoc一元文件测试操作符列表:

    -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 (false if symlinks aren't
        supported by the file system).
    -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 or UTF-8 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)

perldoc-f-e
。这是Perl从
bash
继承的东西。请注意,记录的错误(不存在)可能不正确<代码>$包含实际错误。例如,您可能没有足够的权限检查它是否存在。
perldoc-f-e
。这是Perl从
bash
继承的东西。请注意,记录的错误(不存在)可能不正确<代码>$包含实际错误。例如,您可能没有足够的权限检查它是否存在。
perldoc-f-e
也可以工作。
perldoc-f-e
也可以工作。