Here are some examples of common post variables.  In most cases the word "no" has a value of 0 (zero) and "yes" has a value of 1 (one).  As you can see, these variables can drasticaly change the  NC output.

arcoutput   : 1       #0 = IJK, 1 = R no sign, 2 = R signed neg. over 180
arctype       : 2       #Arc center 1=abs, 2=St-Ctr, 3=Ctr-St, 4=unsigned inc.
breakarcs  : no    #Break arcs into quadrants?
force_wcs : yes   #Force WCS output at every toolchange?
spaces       : 0       #Number of spaces to add between codes.
omitseq     : no     #Omit sequence no. (except at tool changes)
   #### Tool Change Formatting & Staging Options   #####
stagetool   : yes    #0=Do not Stage Tools, 1=Stage Tools & output 1st tool at EOF
tlchgtype   : 0        #0=T#M6 same line, 1=T#M6 sep.line
tooltable    : yes     #Activate Tool table 0=no 1=yes (or yes/no)