From the documentation of the Perl command chmod:

The first element of the list must be the numeric mode, which should probably be an octal number, and which definitely should not be a string of octal digits: 0644 is okay, but "0644" is not.

No mention of being able to specify "u+x" or the like.

Also, having not used Unix for a while, what is the reason to mark a pdf file as executable?

In reply to Re: How to use chmod u +x in perl by hdb
in thread How to use chmod u +x in perl by fearthechris29

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