Perl has a useful set of file test operators that can be used to see if a file exists. There is -e in it, which checks if the file exists. This information may be useful to you when you are working with a script that requires access to a specific file, and you want to ensure that the file exists before performing an operation.
For example, if your script has a dependent log or configuration file, check it first. The example script below raises a descriptive error if the file is not found using this test.
#!/usr/bin/perl $filename = '/path/to/your/file.doc'; if (-e $filename) { print "File Exists!"; }
First, create a string containing the path to the file you want to test. Then wrap the -e(exists) statement in a conditional block so that the print statement (or whatever you put there) is only called if the file exists. You can test the opposite - file does not exist - by using an unless condition:
unless (-e $filename) { print "File Doesn't Exist!"; }
Other File Test Operators
You can use "and" (&&) or "or" (|| ) operator tests two or more things at once. Some other Perl file testing operators are:
Check if the file is readable
w Check if the file is writable
-x Check if the file is executable
-zCheck whether the file is empty
fCheck whether the file is a normal file
-dCheck whether the file is a directory
lCheck whether the file is a symbolic link
Using file testing can help you avoid errors or make you aware of errors that need to be fixed.
Related recommendations: "Perl Tutorial"http://www.php.cn/course/list/39.html
This article This article is about the method of determining whether a file exists in Perl. I hope it will be helpful to friends in need!
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