In one of the shell script (Where abinitio graph is called), the last line is wait ${!}. What does this wait ${!} mean ???
${!} an alternate syntax for $! which is the PID of the last background command (presumably here, your graph application). The script simply waits for the application to finish.
Generally, ${anything} is just another way to write $anything -- in some situations, the braces are required for disambiguation (${anything}too means something else than $anythingtoo which means ${anythingtoo}) but some people like to put them everywhere just out of habit, or for clarity.
Perform the following, you will come to know:
- a man of wait command
- and the following example:
$ sleep 10 &
[2] 9110
$ wait ${!}
And
$! :: PID of last background process
//Jadu