bash - What is the `@Name@` in command line?

Question

I'm looking for Tsung source code. There is a line like following in file tsung.sh.in:

ERL_OPTS=" $ERL_DIST_PORTS -smp auto +P $MAX_PROCESS +A 16 +K true @ERL_OPTS@ "

What does the @ERL_OPTS@ mean?

Answer 1

This seems to be something that gets substituted by autoconf during the build process.

Generally, a .in file gets preprocessed by some build script. Autoconf uses @IDENTIFIER@ to indicate the place where the actual value has to be put in. The preprocessed version loses the .in extension, thus generating tsung.sh in this particular case.