Programming with Perl is fairly straightforward, which runs to the letters you use for file tests. For example, r tests whether a file can be read, and T looks for a text file. Here are most useful file tests in Perl:

Test Description
-e File exists.
-r File can be read.
-w File can be written to.
-z File is exactly zero bytes long.
-d Named item is a directory, not a file.
-T File is a text file. (The first chunk of a file is examined, and it’s a text file if fewer than 30 percent or so of the characters are nonprintable.)
-B File is a binary file. (This is the exact opposite of the -T test — it’s a binary file if more than 30 percent or so of the characters are nonprintable.)
-s Size of the file in bytes.
-C Creation age of file.
-A Access age of file.
-M Modification age of file.