Variable assignment in a ksh script

Question

I am viewing a ksh script and I see a function where the variable has been defined as below. Can anyone explain what exactly the below assignment of variable means in ksh script?

temprule="\$${APPLC_NM}" 

Answer 1

temprule will be assigned '$' followed by the value of the variable APPLC_NM. So if APPLC_NM is set to "pizza", temprule will become "$pizza".

Note that temprule="\$$APPLC_NM" would do the exact same thing. The brackets are only needed when the variable name is followed by a character that would be valid in a variable name.

Answer 2

As @Julie Pelletier indicated, this is funny syntax to make a indirect variable, or a nameref. ksh has some specialized syntax to make this work, however. This is a feature of ksh, and might not work in other shells.

The more idiomatic way to write the same in ksh would look like this:

# Set up the nameref: nameref temprule=APPLC_NM # Assign value to AAPLC_NM APPLC_NM=abc # The above two statements may be executed in any order. # Now, temprule will contain the value of APPLC_NM: echo $temprule abc 

Now, no funny escaping of double $ is necessary, and the result is arguably more readable.