How to Tell if a File Exists in Perl

Perl has a set of useful file test operators that can be used to see whether a file exists or not. Among them is -e, which checks to see if a file exists. This information could be useful to you when you are working on a script that needs access to a specific file, and you want to be sure that the file is there before performing operations. If, for example, your script has a log or a configuration file that it depends upon, check for it first. The example script below throws a descriptive error if a file is not found using this test.

#!/usr/bin/perl
$filename = '/path/to/your/file.doc';
if (-e $filename) {
print "File Exists!";
}

First, you create a string that contains the path to the file that you want to test. Then you 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 could test for the opposite-that the file does not exist-by using the unless conditional:

unless (-e $filename) {
print "File Doesn't Exist!";
}

Other File Test Operators

You can test for two or more things at a time using the "and" (&&) or the "or" (||) operators. Some other Perl file test operators are:

• -r checks if the file is readable
• -w checks if the file is writeable
• -x checks if the file is executable
• -z checks if the file is empty
• -f checks if the file is a plain file
• -d checks if the file is a directory
• -l checks if the file is a symbolic link

Using a file test can help you avoid errors or make you aware of an error that needs to be fixed.