With the -i flag, essmsh uses standard input, which could be input from another process. For example,
program.sh | essmsh -i
When program.sh generates MaxL statements as output, you can pipe program.sh to essmsh -i to use the standard output of program.sh as standard input for essmsh. essmsh receives input as program.sh generates output, allowing for efficient co-execution of scripts.
echo login Fiona sunflower on localhost; display privilege user;|essmsh -i
The MaxL Shell takes input from the echo command's output. User Fiona is logged in, and user privileges are displayed.