Gnuplot, how to *skip* missing data files?

Question

Depending on various factors i may not have 1 or more data files, referenced in pre-defined gnuplot plot instructions, that don\'t exist. When this is the case i get \"w

Answer 1

Here is a similar solution without a helper script

file_exists(file) = system("[ -f '".file."' ] && echo '1' || echo '0'") + 0
if ( file_exists("mydatafile") ) plot "mydatafile" u 1:2 ...

the + 0 part is to convert the result from string to integer, in this way you can also use the negation

if ( ! file_exists("mydatafile") ) print "mydatafile not found."