All tcsh scripts must have # as the first character of the script. When a script file starts with #!, the kernel's spawn and exec services recognize the file name after the #! as the program to be run. It is recommended that the first line of all tcsh scripts look like:

#!/bin/tcsh

with /bin/tcsh being the location of tcsh on the z/OS® system. The kernel recognizes the magic value (#!) and runs /bin/tcsh.