Les Mikesell wrote: > edwardspl@xxxxxxxxxx wrote: > >>>>>> chmod g+rwx ( What number of g+rwx, eg : ?77 ) /home/edward >>>>> >>>>> You can use the symbolic form literally. I think it's easier to >>>>> understand. Let the computer do the binary/octal math. >>>>> g+rwx means add the read, write, and execute bits for the group. >>>> >>>> But I want to know what no of g+rwx... >>> >>> >>> The + means it is added to the bits already permitted. Look at them as >>> groups of 3 bits in binary and take the octal value. >>> >>> user group other >>> rwx rwx rwx >>> >>> You'll start with a home dir having rwx --- --- so that's 111 000 000 >>> binary or 700 octal. >>> Add the group rwx and you get 111 111 000 or 770 octal >> >> So, g+rwx = 770, right ? > > > No.. Literally it means to add the 2nd 7 (the ---rwx--- positions) to > whatever was there before. In the case of a typical home directory it > will be 770 because the first 7 ( rwx------) was already there. So... what is the correct no for the pression limitation ? Or may be chmod g+770 >>> >>> That's one more bit to the left, 1 000 000 000 binary, so 1000 octal. >>> Add that to what you have. >>> >>>>> Same here, you can type it that way and it means add the "sticky" >>>>> bit. >>>> >>>> Also want to know... >>> >>> >>> Altogether, the octal value for the mode ends up at 1770. But, as I >>> said before the computer does a better job of thinking in octal. >> >> So, +t = 1770, right ? > > chmod +t ( What number of +t ) /home/edward > > Again, that is the case where you already have 770 set, but +t really > means to add the 1000 bit to whatever was there. You can also specify > absolute settings in the symbolic style: > chmod u=rwx,g=rwx,o=t file... > will set 1770 regardless of what is there and is easier to understand. > See 'man chmod' for more details, but it helps to know that the modes > are simply bits where 1 gives the permission, 0 does not. The values > you compute in octal show the combinations of the bits but they really > each only have their own independent meaning so I think the symbolic > form makes more sense. > So... is it correct ?
