The fit command will run a certain number of iterations and then query the user whether he or she wants to continue. While useful under most circumstances, the constant questioning can be a pain if one leaves XSPEC running and expects to find it finished when one gets back, or if one habitually runs scripts. One way around this problem is to reset the number of iterations before the question is asked by giving a single argument. For example,
XSPEC12> fit 100
will run 100 iterations before asking a question.
A more drastic solution is to use the query command.
XSPEC12> query yes
This will suppress all questions and assume that their answer is yes, while
XSPEC12> query no
will suppress all questions but assume that their answer is no.
The amount of output that XSPEC writes is set by the chatter command, which takes two arguments applying to the terminal and to the log file.