Please see the attached file for the complete problem.

Please help me with this programming question:

Create a single command string that will modify the file called myfile and change all occurrences of the ! to a :. The command string must also sort the file numerically on the GID field and then save the output to a file called newfile.

Replace the ## in the command string below with the correct characters to make the above described work.
sed 's/!/:/g' myfile | sort -### -t: > ~/newfile