There are a number of very useful tests you can perform on files. Remember that you’ll usually want to determine if the file exists first, especially for the tests that return a value such as a file size or age.
| Test | Tests |
| -e | the file exists |
| -r | the file is readable by your script |
| -w | the file is writable by your script |
| -x | the file is executable by your script |
| -s | the size of the file in bytes |
| -f | the file is a plain file, not a directory or alias |
| -d | the file is a directory |
| -M | the time since the file was last modified, in days |
Tests can be combined by using the filename for the first test, and the underscore for subsequent tests. For example, to test if a file exists and has been modified less than 24 hours ago:
if (-e $filepath && -M _ < 1) { … }
There are many more tests for more specialized purposes, but these should cover most of your needs.
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