Show or set the local time offset, as integer n hours from UTC, or as minutes if abs[n]>23. The initial value of 0N means the machine’s offset is used.

q)\o
0N
q).z.p                        / UTC
2010.05.31D23:45:52.086467000
q).z.P                        / local time is UTC + 8
2010.06.01D07:45:53.830469000
q)\o -5                       / set local time as UTC - 5
q).z.P
2010.05.31D18:45:58.470468000
q)\o 390                      / set local time as UTC + 6:30
q).z.P
2010.06.01D06:16:06.603981000

This corresponds to the -o command line parameter.