Gswap interchanges the values for two marks in a grades file.
gswap [-m mark1 -m mark2] [files]
Gswap exchanges the value of the mark named mark1 with the value of the mark named mark2 in the grades files.
The definitions of mark1 and mark2 are not exchanged in the grades-file header; that must be done by the user, if it is required. Separate-line comments in student records are not altered.
If the mark name options are omitted, gswap interrogates the user for them.
If no files are specified, input comes from the standard input and output goes to the standard output. In this case, the mark name options cannot be omitted.
It is probably a good idea to examine the contents of the files after processing is complete.
The only significant change is that the the mark definitions cannot be swapped in the grades-file header. A minor change is that more than one grades file can be processed.