In addition to what Corion says about placeholders, be aware that quoting, not shown in perldiag, may be added. For instance, that documentation shows this error message: 

Can't find string terminator %s anywhere before EOF

[download]

Consider how that message is subtly changed by adding single quotes (around %s) in the first example below and double quotes in the second example. 

$ cat pm_error_quine
Can't find string terminator " anywhere before EOF at pm_error_quine l
+ine 1.
$ perl pm_error_quine 1> /dev/null
Can't find string terminator '"' anywhere before EOF at pm_error_quine
+ line 1.
$

[download]
$ cat pm_error_quine
Can't find string terminator ` anywhere before EOF at pm_error_quine l
+ine 1.
$ perl pm_error_quine 1> /dev/null
Can't find string terminator "`" anywhere before EOF at pm_error_quine
+ line 1.
$

[download]

-- Ken

In reply to Re^2: Is there a non-empty error quine in perl? by kcott
in thread Is there a non-empty error quine in perl? by ambrus

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