The ESET command is only built in to TEXTCMD.
The ESET command displays and allows the user to interactively edit the value of anenvironment variable in the environment of the command interpreter process.
ESET writes the name and value of the environment variable to standard output, in the form "name=value", and allows the user to edit the value. When the user presses return, the environment variable is set to the new value.
SET SETENV UNSETENV CLEARENV PRINTENV DPATH PATH LIBPATH PROMPT INPUT