Hello, World! in J
1!:2 is the dyadic foreign conjunction for writing text, the left argument is the string to be written and the right argument specifies the file number, a file number 2 indicates that the text is to be written to the screen.
Alternatively we can use currying to convert the dyadic write conjunction into a monadic conjunction using the bond (&) operator and assign it to a named print function.
The printf library may also be used to print text to the screen.
'Hello, World!' 1!:2]2 print=: 1!:2&2 print 'Hello, World!' load 'printf' '' printf 'Hello, World!\n'