Selecting multiple file extensions, when some don't exist

I want to select all files with extension f, F and F90. Currently I am trying something like

echo *.f *.F *.f90

However, if there are no .f files in the directory (and there is always one of the three) I get left with the *.f, i.e it echos

*.f file1.F file2.f90

开发者_如何学运维Which, if I want to delete them will always complain as *.f doesn't exist.

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shopt -s nullglob will fix this in Bash, but is not portable.