How can I add days to the logic in my shell script?

I am on AIX c shell and trying to add days.
I have

#!/bin/sh    

Today=`date +%u` # which gives me 5    
Tomorrow='expr ${Today} + 1' # do nothing    

could you please let me know how to increase day of the week by 1?

Solution 1:

Your problem is you put your expr statement in single quotes, which prevents the shell from replacing ${Today} with 5, and prevents it from executing the expr instruction (it just stores the whole expression as a string in the Tomorrow variable).

You probably want something like this:

#!/bin/sh    

Today=`date +%u` # which gives me 5    
Tomorrow=`expr ${Today} + 1` # works
echo $Tomorrow # outputs 6