Hmm, I get strange warnings about aria (not arial) font not being found
gmt begin tt ps
gmtset FONT arial FONT_TITLE 18p,arial PS_CHAR_ENCODING ISO-8859-7 MAP_DEGREE_SYMBOL degree
gmtset [WARNING]: Length <unit> l not supported - revert to default unit [point]
gmtset [WARNING]: aria not a valid number and may not be decoded properly.
gmtset [WARNING]: Representation of font size not recognized. Using default.
gmtset [WARNING]: Length <unit> l not supported - revert to default unit [point]
gmtset [WARNING]: aria not a valid number and may not be decoded properly.
gmtset [WARNING]: Representation of font size not recognized. Using default.
gmtset [WARNING]: Length <unit> l not supported - revert to default unit [point]
gmtset [WARNING]: aria not a valid number and may not be decoded properly.
gmtset [WARNING]: Representation of font size not recognized. Using default.
gmtset [WARNING]: Length <unit> l not supported - revert to default unit [point]
gmtset [WARNING]: aria not a valid number and may not be decoded properly.
gmtset [WARNING]: Representation of font size not recognized. Using default.
gmtset [WARNING]: Length <unit> l not supported - revert to default unit [point]
gmtset [WARNING]: aria not a valid number and may not be decoded properly.
gmtset [WARNING]: Representation of font size not recognized. Using default.
gmtset [WARNING]: Length <unit> l not supported - revert to default unit [point]
gmtset [WARNING]: aria not a valid number and may not be decoded properly.
gmtset [WARNING]: Representation of font size not recognized. Using default.
gmtset [WARNING]: Length <unit> l not supported - revert to default unit [point]
gmtset [WARNING]: aria not a valid number and may not be decoded properly.
gmtset [WARNING]: Representation of font size not recognized. Using default.
gmtset [WARNING]: Representation of font type not recognized. Using default.
gmt coast -R21.2/21.7/38.35/38.7 -JM19c -Df -N1/thick,black,-- -Slightgray -Ia/.6p -Lfx7/1/38.4/10+l -W.4p -B.5
coast [WARNING]: Changing to PostScript landscape orientation based on your plot and paper dimensions, but we cannot be 100% sure.
coast [WARNING]: Use PS_MEDIA and/or PS_PAGE_ORIENTATION to specify correct paper dimensions and/or orientation if our guesses are inadequate.
gmt text town3.txt -F+f17p,arial+jBL -Dj0.1c -Gwhite -Qu
text [WARNING]: Representation of font type not recognized. Using default.
echo 21.5 38.5 αξηλξκηκλξ | gmt text -F+f17p,arial+jBL -Dj0.1c -Gwhite -Qu
text [WARNING]: Representation of font type not recognized. Using default.
gmt end show